Pub Date : 2024-12-20DOI: 10.3847/2041-8213/ad99da
Xinyi Hong, Ning-Chen Sun, Zexi Niu, Junjie Wu, Qiang Xi and Jifeng Liu
The progenitors of Type II-P supernovae (SN) have been confirmed to be red supergiants. However, the upper mass limit of the directly probed progenitors is much lower than that predicted by current theories, and the accurate determination of the progenitor masses is key to understand the final fate of massive stars. Located at a distance of only 6.72 Mpc, the Type II-P SN 2024ggi is one of the closest SNe in the last decade. Previous studies have analyzed its progenitor by direct detection, but the derived progenitor mass may be influenced by the very uncertain circumstellar extinction and pulsational brightness variability. In this work, we try to constrain the progenitor mass with an environmental analysis based on images from the Hubble Space Telescope. We found that stars in the progenitor environment have a uniform spatial distribution without significant clumpiness, and we derived the star formation history of the environment with a hierarchical Bayesian method. The progenitor is associated with the youngest population in the SN environment with an age of log(t/yr) = 7.41 (i.e., 25.7 Myr), which corresponds to an initial mass of M⊙. Our work provides an independent measurement of the progenitor mass, which is not affected by circumstellar extinction and pulsational brightness variability.
{"title":"Constraining the Progenitor of the Nearby Type II-P SN 2024ggi with Environmental Analysis","authors":"Xinyi Hong, Ning-Chen Sun, Zexi Niu, Junjie Wu, Qiang Xi and Jifeng Liu","doi":"10.3847/2041-8213/ad99da","DOIUrl":"https://doi.org/10.3847/2041-8213/ad99da","url":null,"abstract":"The progenitors of Type II-P supernovae (SN) have been confirmed to be red supergiants. However, the upper mass limit of the directly probed progenitors is much lower than that predicted by current theories, and the accurate determination of the progenitor masses is key to understand the final fate of massive stars. Located at a distance of only 6.72 Mpc, the Type II-P SN 2024ggi is one of the closest SNe in the last decade. Previous studies have analyzed its progenitor by direct detection, but the derived progenitor mass may be influenced by the very uncertain circumstellar extinction and pulsational brightness variability. In this work, we try to constrain the progenitor mass with an environmental analysis based on images from the Hubble Space Telescope. We found that stars in the progenitor environment have a uniform spatial distribution without significant clumpiness, and we derived the star formation history of the environment with a hierarchical Bayesian method. The progenitor is associated with the youngest population in the SN environment with an age of log(t/yr) = 7.41 (i.e., 25.7 Myr), which corresponds to an initial mass of M⊙. Our work provides an independent measurement of the progenitor mass, which is not affected by circumstellar extinction and pulsational brightness variability.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142867177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-20DOI: 10.3847/2041-8213/ad9bb5
Alexander E. Thelen, Katherine de Kleer, Martin A. Cordiner, Imke de Pater, Arielle Moullet and Statia Luszcz-Cook
We present spatially resolved measurements of SO2 and NaCl winds on Io at several unique points in its orbit: before and after eclipse and at maximum eastern and western elongation. The derived wind fields represent a unique case of meteorology in a rarified, volcanic atmosphere. Through the use of Doppler shift measurements in emission spectra obtained with the Atacama Large Millimeter/submillimeter Array between ~346 and 430 GHz (~0.70–0.87 mm), line-of-sight winds up to ~−100 m s−1 in the approaching direction and >250 m s−1 in the receding direction were derived for SO2 at altitudes of ~10–50 km, while NaCl winds consistently reached ~∣150–200∣ m s−1 in localized regions up to ~30 km above the surface. The wind distributions measured at maximum east and west Jovian elongations and on the sub-Jovian hemisphere pre- and posteclipse were found to be significantly different and complex, corroborating the results of simulations that include surface temperature and frost distribution, volcanic activity, and interactions with the Jovian magnetosphere. Further, the wind speeds of SO2 and NaCl are often inconsistent in direction and magnitude, indicating that the processes that drive the winds for the two molecular species are different and potentially uncoupled; while the SO2 wind field can be explained through a combination of sublimation-driven winds, plasma torus interactions, and plume activity, the NaCl winds appear to be primarily driven by the plasma torus.
我们展示了木卫一轨道上几个独特点的SO2和NaCl风的空间分辨率测量结果：日食前后和最大东伸长和最大西伸长。衍生的风场代表了稀薄的火山大气中气象学的一个独特案例。通过对阿塔卡马大型毫米/亚毫米阵列在~346 ~ 430 GHz （~0.70 ~ 0.87 mm）范围内获得的发射光谱进行多普勒频移测量，得出了在~10 ~ 50 km高度上，SO2接近方向的视距风速可达~−100 m s−1，后退方向的视距风速可达~ 250 m s−1，而在距离地面~30 km的局部区域，NaCl风速始终达到~∣150 ~ 200∣m s−1。在日蚀前后，在木星最大的东、西延伸处和次木星半球上测量到的风分布明显不同且复杂，证实了模拟结果，包括表面温度和霜冻分布、火山活动以及与木星磁层的相互作用。此外，SO2和NaCl的风速在方向和量级上往往不一致，这表明驱动这两种分子物种的风的过程是不同的，可能是不耦合的；SO2风场可以通过升华驱动风、等离子体环面相互作用和羽流活动的组合来解释，而NaCl风似乎主要是由等离子体环面驱动的。
{"title":"Io’s SO2 and NaCl Wind Fields from ALMA","authors":"Alexander E. Thelen, Katherine de Kleer, Martin A. Cordiner, Imke de Pater, Arielle Moullet and Statia Luszcz-Cook","doi":"10.3847/2041-8213/ad9bb5","DOIUrl":"https://doi.org/10.3847/2041-8213/ad9bb5","url":null,"abstract":"We present spatially resolved measurements of SO2 and NaCl winds on Io at several unique points in its orbit: before and after eclipse and at maximum eastern and western elongation. The derived wind fields represent a unique case of meteorology in a rarified, volcanic atmosphere. Through the use of Doppler shift measurements in emission spectra obtained with the Atacama Large Millimeter/submillimeter Array between ~346 and 430 GHz (~0.70–0.87 mm), line-of-sight winds up to ~−100 m s−1 in the approaching direction and >250 m s−1 in the receding direction were derived for SO2 at altitudes of ~10–50 km, while NaCl winds consistently reached ~∣150–200∣ m s−1 in localized regions up to ~30 km above the surface. The wind distributions measured at maximum east and west Jovian elongations and on the sub-Jovian hemisphere pre- and posteclipse were found to be significantly different and complex, corroborating the results of simulations that include surface temperature and frost distribution, volcanic activity, and interactions with the Jovian magnetosphere. Further, the wind speeds of SO2 and NaCl are often inconsistent in direction and magnitude, indicating that the processes that drive the winds for the two molecular species are different and potentially uncoupled; while the SO2 wind field can be explained through a combination of sublimation-driven winds, plasma torus interactions, and plume activity, the NaCl winds appear to be primarily driven by the plasma torus.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142867192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-19DOI: 10.3847/2041-8213/ad9917
Juan-Juan Luo, Liang Zhang, Li-Yun Zhang, Yong-Feng Huang, Jia-Quan Lin, Jun-Wang Lu and Xiao-Fei Dong
Gamma-ray bursts (GRBs) are usually classified into long/short categories according to their durations, but controversy still exists in this aspect. Here we reexamine the long/short classification of GRBs and further compare the cosmological distribution and evolution of each potential subclass. A large number of Swift Burst Alert Telescope (BAT) GRBs are analyzed in this study. The Gaussian mixture model is used to fit the duration distribution as well as the joint distribution of duration and hardness ratio, and the Akaike and Bayesian information criteria are adopted to assess the goodness of fit. It is found that three Gaussian components can better fit both the univariate and bivariate distributions, indicating that there are three subclasses in the Swift/BAT GRBs, namely, short, intermediate, and long subclasses. The nonparametric Efron–Petrosian and Lynden-Bell's c− methods are used to derive the luminosity function and formation rate from the truncated data of bursts with known redshift in each subclass. It is found that the luminosity distributions and birth rates of the three subclasses are different, further supporting the existence of the intermediate subclass in the Swift/BAT GRBs.
{"title":"The Classification and Formation Rate of Swift/BAT Gamma-Ray Bursts","authors":"Juan-Juan Luo, Liang Zhang, Li-Yun Zhang, Yong-Feng Huang, Jia-Quan Lin, Jun-Wang Lu and Xiao-Fei Dong","doi":"10.3847/2041-8213/ad9917","DOIUrl":"https://doi.org/10.3847/2041-8213/ad9917","url":null,"abstract":"Gamma-ray bursts (GRBs) are usually classified into long/short categories according to their durations, but controversy still exists in this aspect. Here we reexamine the long/short classification of GRBs and further compare the cosmological distribution and evolution of each potential subclass. A large number of Swift Burst Alert Telescope (BAT) GRBs are analyzed in this study. The Gaussian mixture model is used to fit the duration distribution as well as the joint distribution of duration and hardness ratio, and the Akaike and Bayesian information criteria are adopted to assess the goodness of fit. It is found that three Gaussian components can better fit both the univariate and bivariate distributions, indicating that there are three subclasses in the Swift/BAT GRBs, namely, short, intermediate, and long subclasses. The nonparametric Efron–Petrosian and Lynden-Bell's c− methods are used to derive the luminosity function and formation rate from the truncated data of bursts with known redshift in each subclass. It is found that the luminosity distributions and birth rates of the three subclasses are different, further supporting the existence of the intermediate subclass in the Swift/BAT GRBs.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"79 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142858312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-18DOI: 10.3847/2041-8213/ad823b
Eduardo Bañados, Yana Khusanova, Roberto Decarli, Emmanuel Momjian, Fabian Walter, Thomas Connor, Christopher L. Carilli, Chiara Mazzucchelli, Sofía Rojas-Ruiz and Bram P. Venemans
We present millimeter observations of the host galaxy of the most distant blazar known, VLASS J041009.05−013919.88 (hereafter J0410–0139) at z = 7, using Atacama Large Millimeter/submillimeter Array (ALMA) and NOrthern Extended Millimeter Array (NOEMA) observations. The ALMA data reveal a (2.02 ± 0.36) × 1042 erg s−1 [C ii] 158 μm emission line at z = 6.9964 with a [C ii]-inferred star formation rate (SFR) of 58 ± 9 M⊙ yr−1. We estimate a dynamical mass of Mdyn,[C ii] = (4.6 ± 2.0) × 109M⊙, implying a black hole mass to host a dynamical mass ratio of . The 238 GHz continuum (rest-frame IR) decreased by ∼33% from the NOEMA to the ALMA observations taken ∼10 months apart. The Very Large Array 3–10 GHz radio flux densities showed a ∼37% decrease in a similar time frame, suggesting a causal connection. At face value, J0410–0139 would have the lowest [C ii]-to-IR luminosity ratio of a z > 5.7 quasar reported to date (∼10−4). However, if only <20% of the measured IR luminosity was due to thermal emission from dust, the [C ii]-to-IR luminosity ratio would be typical of (U)LIRGs, and the SFRs derived from [C ii] and IR luminosities would be consistent. These results provide further evidence that synchrotron emission significantly contributes to the observed rest-frame IR emission of J0410–0139, similar to what has been reported in some radio-loud active galactic nuclei at z < 1.
{"title":"[C ii] Properties and Far-infrared Variability of a z = 7 Blazar","authors":"Eduardo Bañados, Yana Khusanova, Roberto Decarli, Emmanuel Momjian, Fabian Walter, Thomas Connor, Christopher L. Carilli, Chiara Mazzucchelli, Sofía Rojas-Ruiz and Bram P. Venemans","doi":"10.3847/2041-8213/ad823b","DOIUrl":"https://doi.org/10.3847/2041-8213/ad823b","url":null,"abstract":"We present millimeter observations of the host galaxy of the most distant blazar known, VLASS J041009.05−013919.88 (hereafter J0410–0139) at z = 7, using Atacama Large Millimeter/submillimeter Array (ALMA) and NOrthern Extended Millimeter Array (NOEMA) observations. The ALMA data reveal a (2.02 ± 0.36) × 1042 erg s−1 [C ii] 158 μm emission line at z = 6.9964 with a [C ii]-inferred star formation rate (SFR) of 58 ± 9 M⊙ yr−1. We estimate a dynamical mass of Mdyn,[C ii] = (4.6 ± 2.0) × 109M⊙, implying a black hole mass to host a dynamical mass ratio of . The 238 GHz continuum (rest-frame IR) decreased by ∼33% from the NOEMA to the ALMA observations taken ∼10 months apart. The Very Large Array 3–10 GHz radio flux densities showed a ∼37% decrease in a similar time frame, suggesting a causal connection. At face value, J0410–0139 would have the lowest [C ii]-to-IR luminosity ratio of a z > 5.7 quasar reported to date (∼10−4). However, if only <20% of the measured IR luminosity was due to thermal emission from dust, the [C ii]-to-IR luminosity ratio would be typical of (U)LIRGs, and the SFRs derived from [C ii] and IR luminosities would be consistent. These results provide further evidence that synchrotron emission significantly contributes to the observed rest-frame IR emission of J0410–0139, similar to what has been reported in some radio-loud active galactic nuclei at z < 1.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-18DOI: 10.3847/2041-8213/ad991e
Michael M. Shara, Kenneth M. Lanzetta, Alexandra Masegian, James T. Garland, Stefan Gromoll, Joanna Mikolajewska, Mikita Misiura, David Valls-Gabaud, Frederick M. Walter and John K. Webb
A century or less separates the thermonuclear-powered eruptions of recurrent novae (RNe) in the hydrogen-rich envelopes of massive white dwarfs. The colliding ejecta of successive RN events are predicted to always generate very large (tens of parsecs) super-remnants; only two examples are currently known. T CrB offers an excellent opportunity to test this prediction. As it will almost certainly undergo its next, once in ∼80 yr RN event between 2024 and 2026, we carried out very deep narrowband and continuum imaging to search for the predicted, piled-up ejecta of the past millennia. While nothing is detected in continuum or narrowband [O iii] images, a ∼30 pc diameter, faint nebulosity surrounding T CrB is clearly present in deep Hα, [N ii], and [S ii] narrowband Condor Array Telescope imagery. We predict that these newly detected nebulosities, as well as the recent ejecta that have not yet reached the super-remnant, are far too optically thin to capture all but a tiny fraction of the photons emitted by RN flashes. We thus predict that fluorescent light echoes will not be detectable following the imminent nova flash of T CrB. Dust may be released by the T CrB red giant wind in preeruption outbursts, but we have no reliable estimates of its quantity or geometrical distribution. While we cannot predict the morphology or intensity of dust-induced continuum light echoes following the coming flash, we encourage multiepoch Hubble Space Telescope optical imaging as well as James Webb Space Telescope infrared imaging of T CrB during the year after it erupts.
{"title":"The Newly Discovered Nova Super-remnant Surrounding Recurrent Nova T Coronae Borealis: Will it Light Up during the Coming Eruption?","authors":"Michael M. Shara, Kenneth M. Lanzetta, Alexandra Masegian, James T. Garland, Stefan Gromoll, Joanna Mikolajewska, Mikita Misiura, David Valls-Gabaud, Frederick M. Walter and John K. Webb","doi":"10.3847/2041-8213/ad991e","DOIUrl":"https://doi.org/10.3847/2041-8213/ad991e","url":null,"abstract":"A century or less separates the thermonuclear-powered eruptions of recurrent novae (RNe) in the hydrogen-rich envelopes of massive white dwarfs. The colliding ejecta of successive RN events are predicted to always generate very large (tens of parsecs) super-remnants; only two examples are currently known. T CrB offers an excellent opportunity to test this prediction. As it will almost certainly undergo its next, once in ∼80 yr RN event between 2024 and 2026, we carried out very deep narrowband and continuum imaging to search for the predicted, piled-up ejecta of the past millennia. While nothing is detected in continuum or narrowband [O iii] images, a ∼30 pc diameter, faint nebulosity surrounding T CrB is clearly present in deep Hα, [N ii], and [S ii] narrowband Condor Array Telescope imagery. We predict that these newly detected nebulosities, as well as the recent ejecta that have not yet reached the super-remnant, are far too optically thin to capture all but a tiny fraction of the photons emitted by RN flashes. We thus predict that fluorescent light echoes will not be detectable following the imminent nova flash of T CrB. Dust may be released by the T CrB red giant wind in preeruption outbursts, but we have no reliable estimates of its quantity or geometrical distribution. While we cannot predict the morphology or intensity of dust-induced continuum light echoes following the coming flash, we encourage multiepoch Hubble Space Telescope optical imaging as well as James Webb Space Telescope infrared imaging of T CrB during the year after it erupts.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"64 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142848991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-18DOI: 10.3847/2041-8213/ad95e8
Chih-Chun Hsu, Jason J. Wang, 劲飞 王, Geoffrey A. Blake, Jerry W. Xuan, Yapeng Zhang, Jean-Baptiste Ruffio, Katelyn Horstman, Julianne Cronin, Ben Sappey, Yinzi Xin, Luke Finnerty, Daniel Echeverri, Dimitri Mawet, Nemanja Jovanovic, Clarissa R. Do Ó, Ashley Baker, Randall Bartos, Benjamin Calvin, Sylvain Cetre, Jacques-Robert Delorme, Gregory W. Doppmann, Michael P. Fitzgerald, Joshua Liberman, Ronald A. López, Evan Morris, Jacklyn Pezzato-Rovner, Tobias Schofield, Andrew Skemer, J. Kent Wallace, Ji Wang and 吉 王
The ~5 Myr PDS 70 is the only known system with protoplanets residing in the cavity of the circumstellar disk from which they formed, ideal for studying exoplanet formation and evolution within its natal environment. Here, we report the first spin constraint and C/O measurement of PDS 70b from Keck/KPIC high-resolution spectroscopy. We detected CO (3.8σ) and H2O (3.5σ) molecules in the PDS 70b atmosphere via cross correlation, with a combined CO and H2O template detection significance of 4.2σ. Our forward-model fits, using BT-Settl model grids, provide an upper limit for the spin rate of PDS 70b (<29 km s−1). The atmospheric retrievals constrain the PDS 70b C/O ratio to (<0.63 under 95% confidence level) and a metallicity [C/H] of dex, consistent with that of its host star. The following scenarios can explain our measured C/O of PDS 70b in contrast with that of the gas-rich outer disk (for which C/O ≳ 1). First, the bulk composition of PDS 70b might be dominated by dust+ice aggregates rather than disk gas. Another possible explanation is that the disk became carbon enriched after PDS 70b was formed, as predicted in models of disk chemical evolution and as observed in both very low-mass stars and older disk systems with JWST/MIRI. Because PDS 70b continues to accrete and its chemical evolution is not yet complete, more sophisticated modeling of the planet and the disk, and higher-quality observations of PDS 70b (and possibly PDS 70c), are necessary to validate these scenarios.
{"title":"PDS 70b Shows Stellar-like Carbon-to-oxygen Ratio","authors":"Chih-Chun Hsu, Jason J. Wang, 劲飞 王, Geoffrey A. Blake, Jerry W. Xuan, Yapeng Zhang, Jean-Baptiste Ruffio, Katelyn Horstman, Julianne Cronin, Ben Sappey, Yinzi Xin, Luke Finnerty, Daniel Echeverri, Dimitri Mawet, Nemanja Jovanovic, Clarissa R. Do Ó, Ashley Baker, Randall Bartos, Benjamin Calvin, Sylvain Cetre, Jacques-Robert Delorme, Gregory W. Doppmann, Michael P. Fitzgerald, Joshua Liberman, Ronald A. López, Evan Morris, Jacklyn Pezzato-Rovner, Tobias Schofield, Andrew Skemer, J. Kent Wallace, Ji Wang and 吉 王","doi":"10.3847/2041-8213/ad95e8","DOIUrl":"https://doi.org/10.3847/2041-8213/ad95e8","url":null,"abstract":"The ~5 Myr PDS 70 is the only known system with protoplanets residing in the cavity of the circumstellar disk from which they formed, ideal for studying exoplanet formation and evolution within its natal environment. Here, we report the first spin constraint and C/O measurement of PDS 70b from Keck/KPIC high-resolution spectroscopy. We detected CO (3.8σ) and H2O (3.5σ) molecules in the PDS 70b atmosphere via cross correlation, with a combined CO and H2O template detection significance of 4.2σ. Our forward-model fits, using BT-Settl model grids, provide an upper limit for the spin rate of PDS 70b (<29 km s−1). The atmospheric retrievals constrain the PDS 70b C/O ratio to (<0.63 under 95% confidence level) and a metallicity [C/H] of dex, consistent with that of its host star. The following scenarios can explain our measured C/O of PDS 70b in contrast with that of the gas-rich outer disk (for which C/O ≳ 1). First, the bulk composition of PDS 70b might be dominated by dust+ice aggregates rather than disk gas. Another possible explanation is that the disk became carbon enriched after PDS 70b was formed, as predicted in models of disk chemical evolution and as observed in both very low-mass stars and older disk systems with JWST/MIRI. Because PDS 70b continues to accrete and its chemical evolution is not yet complete, more sophisticated modeling of the planet and the disk, and higher-quality observations of PDS 70b (and possibly PDS 70c), are necessary to validate these scenarios.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"115 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142848984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-18DOI: 10.3847/2041-8213/ad9744
Melanie J. Rowland, Caroline V. Morley, Brittany E. Miles, Genaro Suarez, Jacqueline K. Faherty, Andrew J. Skemer, Samuel A. Beiler, Michael R. Line, Gordon L. Bjoraker, Jonathan J. Fortney, Johanna M. Vos, Sherelyn Alejandro Merchan, Mark Marley, Ben Burningham, Richard Freedman, Ehsan Gharib-Nezhad, Natasha Batalha, Roxana Lupu, Channon Visscher, Adam C. Schneider, T. R. Geballe, Aarynn Carter, Katelyn Allers, James Mang, Dániel Apai, Mary Anne Limbach and Mikayla J. Wilson
The coldest Y spectral type brown dwarfs are similar in mass and temperature to cool and warm (∼200–400 K) giant exoplanets. We can therefore use their atmospheres as proxies for planetary atmospheres, testing our understanding of physics and chemistry for these complex, cool worlds. At these cold temperatures, their atmospheres are cold enough for water clouds to form, and chemical timescales increase, increasing the likelihood of disequilibrium chemistry compared to warmer classes of planets. JWST observations are revolutionizing the characterization of these worlds with high signal-to-noise, moderate-resolution near- and mid-infrared spectra. The spectra have been used to measure the abundances of prominent species, like water, methane, and ammonia; species that trace chemical reactions, like carbon monoxide; and even isotopologues of carbon monoxide and ammonia. Here, we present atmospheric retrieval results using both published fixed-slit (Guaranteed Time Observation program 1230) and new averaged time series observations (GO program 2327) of the coldest known Y dwarf, WISE 0855–0714 (using NIRSpec G395M spectra), which has an effective temperature of ∼264 K. We present a detection of deuterium in an atmosphere outside of the solar system via a relative measurement of deuterated methane (CH3D) and standard methane. From this, we infer the D/H ratio of a substellar object outside the solar system for the first time. We also present a well-constrained part-per-billion abundance of phosphine (PH3). We discuss our interpretation of these results and the implications for brown dwarf and giant exoplanet formation and evolution.
{"title":"Protosolar D-to-H Abundance and One Part per Billion PH3 in the Coldest Brown Dwarf","authors":"Melanie J. Rowland, Caroline V. Morley, Brittany E. Miles, Genaro Suarez, Jacqueline K. Faherty, Andrew J. Skemer, Samuel A. Beiler, Michael R. Line, Gordon L. Bjoraker, Jonathan J. Fortney, Johanna M. Vos, Sherelyn Alejandro Merchan, Mark Marley, Ben Burningham, Richard Freedman, Ehsan Gharib-Nezhad, Natasha Batalha, Roxana Lupu, Channon Visscher, Adam C. Schneider, T. R. Geballe, Aarynn Carter, Katelyn Allers, James Mang, Dániel Apai, Mary Anne Limbach and Mikayla J. Wilson","doi":"10.3847/2041-8213/ad9744","DOIUrl":"https://doi.org/10.3847/2041-8213/ad9744","url":null,"abstract":"The coldest Y spectral type brown dwarfs are similar in mass and temperature to cool and warm (∼200–400 K) giant exoplanets. We can therefore use their atmospheres as proxies for planetary atmospheres, testing our understanding of physics and chemistry for these complex, cool worlds. At these cold temperatures, their atmospheres are cold enough for water clouds to form, and chemical timescales increase, increasing the likelihood of disequilibrium chemistry compared to warmer classes of planets. JWST observations are revolutionizing the characterization of these worlds with high signal-to-noise, moderate-resolution near- and mid-infrared spectra. The spectra have been used to measure the abundances of prominent species, like water, methane, and ammonia; species that trace chemical reactions, like carbon monoxide; and even isotopologues of carbon monoxide and ammonia. Here, we present atmospheric retrieval results using both published fixed-slit (Guaranteed Time Observation program 1230) and new averaged time series observations (GO program 2327) of the coldest known Y dwarf, WISE 0855–0714 (using NIRSpec G395M spectra), which has an effective temperature of ∼264 K. We present a detection of deuterium in an atmosphere outside of the solar system via a relative measurement of deuterated methane (CH3D) and standard methane. From this, we infer the D/H ratio of a substellar object outside the solar system for the first time. We also present a well-constrained part-per-billion abundance of phosphine (PH3). We discuss our interpretation of these results and the implications for brown dwarf and giant exoplanet formation and evolution.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142848986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-17DOI: 10.3847/2041-8213/ad9264
C. R. Angus, S. E. Woosley, R. J. Foley, M. Nicholl, V. A. Villar, K. Taggart, M. Pursiainen, P. Ramsden, S. Srivastav, H. F. Stevance, T. Moore, K. Auchettl, W. B. Hoogendam, N. Khetan, S. K. Yadavalli, G. Dimitriadis, A. Gagliano, M. R. Siebert, A. Aamer, T. de Boer, K. C. Chambers, A. Clocchiatti, D. A. Coulter, M. R. Drout, D. Farias, M. D. Fulton, C. Gall, H. Gao, L. Izzo, D. O. Jones, C.-C. Lin, E. A. Magnier, G. Narayan, E. Ramirez-Ruiz, C. L. Ransome, A. Rest, S. J. Smartt and K. W. Smith
We present multiwavelength data of SN 2020acct, a double-peaked stripped-envelope supernova (SN) in NGC 2981 at ∼150 Mpc. The two peaks are temporally distinct, with maxima separated by 58 rest-frame days and a factor of 20 reduction in flux between. The first is luminous (Mr = −18.00 ± 0.02 mag) and blue (g − r = 0.27 ± 0.03 mag) and displays spectroscopic signatures of interaction with hydrogen-free circumstellar material. The second peak is fainter (Mr = −17.29 ± 0.03 mag) and has some spectroscopic similarities to an evolved stripped-envelope SN, with strong forbidden [Ca ii] and [O ii] features. No other known double-peaked SN exhibits a light curve similar to that of SN 2020acct. We find the likelihood of two individual SNe occurring in the same star-forming region within that time to be highly improbable, while an implausibly fine-tuned configuration would be required to produce two SNe from a single binary system. We find that the peculiar properties of SN 2020acct match models of pulsational pair instability (PPI), in which the initial peak is produced by collisions of shells of ejected material, shortly followed by core collapse. Pulsations from a star with a 72 M⊙ helium core provide an excellent match to the double-peaked light curve. The local galactic environment has a metallicity of 0.4 Z⊙, a level where massive single stars are not expected to retain enough mass to encounter the PPI. However, late binary mergers or a low-metallicity pocket may allow the required core mass. We measure the rate of SN 2020acct–like events to be <3.3 × 10−8 Mpc−3 yr−1 at z = 0.07, or <0.1% of the total core-collapse SN rate.
{"title":"Double “acct”: A Distinct Double-peaked Supernova Matching Pulsational Pair Instability Models","authors":"C. R. Angus, S. E. Woosley, R. J. Foley, M. Nicholl, V. A. Villar, K. Taggart, M. Pursiainen, P. Ramsden, S. Srivastav, H. F. Stevance, T. Moore, K. Auchettl, W. B. Hoogendam, N. Khetan, S. K. Yadavalli, G. Dimitriadis, A. Gagliano, M. R. Siebert, A. Aamer, T. de Boer, K. C. Chambers, A. Clocchiatti, D. A. Coulter, M. R. Drout, D. Farias, M. D. Fulton, C. Gall, H. Gao, L. Izzo, D. O. Jones, C.-C. Lin, E. A. Magnier, G. Narayan, E. Ramirez-Ruiz, C. L. Ransome, A. Rest, S. J. Smartt and K. W. Smith","doi":"10.3847/2041-8213/ad9264","DOIUrl":"https://doi.org/10.3847/2041-8213/ad9264","url":null,"abstract":"We present multiwavelength data of SN 2020acct, a double-peaked stripped-envelope supernova (SN) in NGC 2981 at ∼150 Mpc. The two peaks are temporally distinct, with maxima separated by 58 rest-frame days and a factor of 20 reduction in flux between. The first is luminous (Mr = −18.00 ± 0.02 mag) and blue (g − r = 0.27 ± 0.03 mag) and displays spectroscopic signatures of interaction with hydrogen-free circumstellar material. The second peak is fainter (Mr = −17.29 ± 0.03 mag) and has some spectroscopic similarities to an evolved stripped-envelope SN, with strong forbidden [Ca ii] and [O ii] features. No other known double-peaked SN exhibits a light curve similar to that of SN 2020acct. We find the likelihood of two individual SNe occurring in the same star-forming region within that time to be highly improbable, while an implausibly fine-tuned configuration would be required to produce two SNe from a single binary system. We find that the peculiar properties of SN 2020acct match models of pulsational pair instability (PPI), in which the initial peak is produced by collisions of shells of ejected material, shortly followed by core collapse. Pulsations from a star with a 72 M⊙ helium core provide an excellent match to the double-peaked light curve. The local galactic environment has a metallicity of 0.4 Z⊙, a level where massive single stars are not expected to retain enough mass to encounter the PPI. However, late binary mergers or a low-metallicity pocket may allow the required core mass. We measure the rate of SN 2020acct–like events to be <3.3 × 10−8 Mpc−3 yr−1 at z = 0.07, or <0.1% of the total core-collapse SN rate.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-16DOI: 10.3847/2041-8213/ad97b9
Deaglan J. Bartlett, Matthew Ho and Benjamin D. Wandelt
Bias models relating the dark matter field to the spatial distribution of halos are widely used in current cosmological analyses. Many models predict halos purely from the local Eulerian matter density, yet bias models in perturbation theory require other local properties. We assess the validity of assuming that only the local dark matter density can be used to predict the number density of halos in a model-independent way and in the nonperturbative regime. Utilizing N-body simulations, we study the properties of the halo counts field after spatial voxels with near-equal dark matter density have been permuted. If local-in-matter-density (LIMD) biasing were valid, the statistical properties of the permuted and unpermuted fields would be indistinguishable since both represent equally fair draws of the stochastic biasing model. If the Lagrangian radius is greater than approximately half the voxel size and for halos less massive than ∼1015h−1M☉, we find the permuted halo field has a scale-dependent bias with greater than 25% more power on scales relevant for current surveys. These bias models remove small-scale power by not modeling correlations between neighboring voxels, which substantially boosts large-scale power to conserve the field’s total variance. This conclusion is robust to the choice of initial conditions and cosmology. Assuming LIMD halo biasing cannot, therefore, reproduce the distribution of halos across a large range of scales and halo masses, no matter how complex the model. One must either allow the biasing to be a function of other quantities and/or remove the assumption that neighboring voxels are statistically independent.
{"title":"Bye-bye, Local-in-matter-density Bias: The Statistics of the Halo Field Are Poorly Determined by the Local Mass Density","authors":"Deaglan J. Bartlett, Matthew Ho and Benjamin D. Wandelt","doi":"10.3847/2041-8213/ad97b9","DOIUrl":"https://doi.org/10.3847/2041-8213/ad97b9","url":null,"abstract":"Bias models relating the dark matter field to the spatial distribution of halos are widely used in current cosmological analyses. Many models predict halos purely from the local Eulerian matter density, yet bias models in perturbation theory require other local properties. We assess the validity of assuming that only the local dark matter density can be used to predict the number density of halos in a model-independent way and in the nonperturbative regime. Utilizing N-body simulations, we study the properties of the halo counts field after spatial voxels with near-equal dark matter density have been permuted. If local-in-matter-density (LIMD) biasing were valid, the statistical properties of the permuted and unpermuted fields would be indistinguishable since both represent equally fair draws of the stochastic biasing model. If the Lagrangian radius is greater than approximately half the voxel size and for halos less massive than ∼1015h−1M☉, we find the permuted halo field has a scale-dependent bias with greater than 25% more power on scales relevant for current surveys. These bias models remove small-scale power by not modeling correlations between neighboring voxels, which substantially boosts large-scale power to conserve the field’s total variance. This conclusion is robust to the choice of initial conditions and cosmology. Assuming LIMD halo biasing cannot, therefore, reproduce the distribution of halos across a large range of scales and halo masses, no matter how complex the model. One must either allow the biasing to be a function of other quantities and/or remove the assumption that neighboring voxels are statistically independent.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142825443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-16DOI: 10.3847/2041-8213/ad99d8
Mohamad Shalaby
Energy dissipation in collisionless shocks is a key mechanism in various astrophysical environments. Its nonlinear nature complicates analytical understanding and necessitates particle-in-cell (PIC) simulations. This study examines the impact of reducing the ion-to-electron mass ratio (mr), to decrease computational cost, on energy partitioning in one spatial and three velocity-space dimension PIC simulations of strong, nonrelativistic, parallel electron–ion collisionless shocks using the SHARP code. We compare simulations with a reduced mass ratio (mr = 100) to those with a realistic mass ratio (mr = 1836) for shocks with high ( ) and low ( ) Alfvén Mach numbers. Our findings show that the mass ratio significantly affects particle acceleration and thermal energy dissipation. At high , a reduced mass ratio leads to more efficient electron acceleration and an unrealistically high ion flux at higher momentum. At low , it causes complete suppression of electron acceleration, whereas the realistic mass ratio enables efficient electron acceleration. The reduced mass ratio also results in excessive electron heating and lower heating in downstream ions at both Mach numbers, with slightly more magnetic field amplification at low . Consequently, the electron-to-ion temperature ratio is high at low due to reduced ion heating and remains high at high due to increased electron heating. In contrast, simulations with the realistic mr show that the ion-to-electron temperature ratio is independent of the upstream magnetic field, a result not observed in reduced mr simulations.
{"title":"Energy Dissipation in Strong Collisionless Shocks: The Crucial Role of Ion-to-electron Scale Separation in Particle-in-cell Simulations","authors":"Mohamad Shalaby","doi":"10.3847/2041-8213/ad99d8","DOIUrl":"https://doi.org/10.3847/2041-8213/ad99d8","url":null,"abstract":"Energy dissipation in collisionless shocks is a key mechanism in various astrophysical environments. Its nonlinear nature complicates analytical understanding and necessitates particle-in-cell (PIC) simulations. This study examines the impact of reducing the ion-to-electron mass ratio (mr), to decrease computational cost, on energy partitioning in one spatial and three velocity-space dimension PIC simulations of strong, nonrelativistic, parallel electron–ion collisionless shocks using the SHARP code. We compare simulations with a reduced mass ratio (mr = 100) to those with a realistic mass ratio (mr = 1836) for shocks with high ( ) and low ( ) Alfvén Mach numbers. Our findings show that the mass ratio significantly affects particle acceleration and thermal energy dissipation. At high , a reduced mass ratio leads to more efficient electron acceleration and an unrealistically high ion flux at higher momentum. At low , it causes complete suppression of electron acceleration, whereas the realistic mass ratio enables efficient electron acceleration. The reduced mass ratio also results in excessive electron heating and lower heating in downstream ions at both Mach numbers, with slightly more magnetic field amplification at low . Consequently, the electron-to-ion temperature ratio is high at low due to reduced ion heating and remains high at high due to increased electron heating. In contrast, simulations with the realistic mr show that the ion-to-electron temperature ratio is independent of the upstream magnetic field, a result not observed in reduced mr simulations.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：