Pub Date : 2024-02-05DOI: 10.1088/1538-3873/ad1ed3
Atila Poro, Mehmet Tanriver, Raul Michel, Ehsan Paki
Multiband photometric investigations for eight binary systems of the W Ursae Majoris-type are presented. Six systems are presented for the first time to analyze their light curves. All the analyzed systems have a temperature below 5000 K and an orbital period of less than 0.28 days. We extracted primary and secondary minima from the ground-based observations of these systems. According to a few observations reported in the literature, linear fits were considered in the O − C diagrams, and new ephemerides were presented. Light curve solutions were performed using the PHysics Of Eclipsing BinariEs code. The results of the mass ratio and fillout factor indicate that the systems are contact binary stars. Six of them showed the O’Connell effect, and a cold starspot on each companion was required for light curve solutions. Their absolute parameters were estimated and evaluated by two other methods. In this study, the empirical relationship between the orbital period and semimajor axis was updated using a sample consisting of 414 contact binary systems and the Monte Carlo Markov Chain approach. Also, using Machine Learning and the Artificial Neural Network model, the relationship between P–T1–M1 was updated for a better estimation of the mass of the primary star.
本文介绍了对八个大熊座W型双星系统的多波段测光研究。其中六个系统的光变曲线分析是首次提出。所有分析的系统温度都低于 5000 K，轨道周期小于 0.28 天。我们从这些系统的地面观测数据中提取了主极小值和次极小值。根据文献中报道的一些观测数据，我们考虑对 O - C 图进行线性拟合，并提出了新的星历表。光变曲线的求解使用了 "PHysics Of Eclipsing BinariEs "代码。质量比和填充因子的结果表明，这些系统是接触双星。其中六颗出现了奥康纳尔效应，每个伴星上都需要一个冷星斑来进行光曲线求解。它们的绝对参数是用另外两种方法估算和评价的。在这项研究中，利用由 414 个接触双星系统组成的样本和蒙特卡罗马尔可夫链方法更新了轨道周期和半长轴之间的经验关系。此外，还利用机器学习和人工神经网络模型更新了 P-T1-M1 之间的关系，以便更好地估计主星的质量。
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We present a data reduction pipeline written in Python for data obtained with the near-infrared cross-dispersed echelle spectrograph, WINERED, which yields a 0.91–1.35 μm spectrum with the resolving power of Rmax≡λ/Δλ=28,000 or 70,000 depending on the observing mode. The pipeline was developed to efficiently extract the spectrum from the raw data with high quality. It comprises two modes: the calibration and the science mode. The calibration mode automatically produces the flat-fielding image, bad pixel map, echellogram distortion map and the dispersion solution from the set of the calibration data. Using calibration images and parameters, the science data of astronomical objects can be reduced automatically using the science mode. The science mode is also used for the real-time quick look at the data during observations. An example of the spectra reduced with WARP is presented. The effect of the highly inclined slit image on the spectral resolution is discussed.
{"title":"WARP: The Data Reduction Pipeline for the WINERED Spectrograph","authors":"Satoshi Hamano, Yuji Ikeda, Shogo Otsubo, Haruki Katoh, Kei Fukue, Noriyuki Matsunaga, Daisuke Taniguchi, Hideyo Kawakita, Keiichi Takenaka, Sohei Kondo, Hiroaki Sameshima","doi":"10.1088/1538-3873/ad1b38","DOIUrl":"https://doi.org/10.1088/1538-3873/ad1b38","url":null,"abstract":"We present a data reduction pipeline written in Python for data obtained with the near-infrared cross-dispersed echelle spectrograph, WINERED, which yields a 0.91–1.35 <italic toggle=\"yes\">μ</italic>m spectrum with the resolving power of <inline-formula>\u0000<tex-math>\u0000<?CDATA ${R}_{max }equiv lambda /{rm{Delta }}lambda ={rm{28,000}}$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msub><mml:mrow><mml:mi>R</mml:mi></mml:mrow><mml:mrow><mml:mi>max</mml:mi></mml:mrow></mml:msub><mml:mo>≡</mml:mo><mml:mi>λ</mml:mi><mml:mrow><mml:mo stretchy=\"true\">/</mml:mo></mml:mrow><mml:mi mathvariant=\"normal\">Δ</mml:mi><mml:mi>λ</mml:mi><mml:mo>=</mml:mo><mml:mi mathvariant=\"normal\">28,000</mml:mi></mml:math>\u0000<inline-graphic xlink:href=\"paspad1b38ieqn1.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> or 70,000 depending on the observing mode. The pipeline was developed to efficiently extract the spectrum from the raw data with high quality. It comprises two modes: the calibration and the science mode. The calibration mode automatically produces the flat-fielding image, bad pixel map, echellogram distortion map and the dispersion solution from the set of the calibration data. Using calibration images and parameters, the science data of astronomical objects can be reduced automatically using the science mode. The science mode is also used for the real-time quick look at the data during observations. An example of the spectra reduced with WARP is presented. The effect of the highly inclined slit image on the spectral resolution is discussed.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139764562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-01DOI: 10.1088/1538-3873/ad1f3e
Zhiyuan Ma, Haojing Yan, Bangzheng Sun, Seth H. Cohen, Rolf A. Jansen, Jake Summers, Rogier A. Windhorst, Jordan C. J. D’Silva, Anton M. Koekemoer, Dan Coe, Christopher J. Conselice, Simon P. Driver, Brenda Frye, Norman A. Grogin, Madeline A. Marshall, Mario Nonino, Rafael Ortiz, Nor Pirzkal, Aaron Robotham, Russell E. Ryan, Christopher N. A. Willmer, Heidi B. Hammel, Stefanie N. Milam, Nathan J. Adams, Cheng Cheng, Nimish P. Hathi
The Prime Extragalactic Areas for Reionization and Lensing Science, a James Webb Space Telescope (JWST) GTO program, obtained a set of unique NIRCam observations that have enabled us to significantly improve the default photometric calibration across both NIRCam modules. The observations consisted of three epochs of 4-band (F150W, F200W, F356W, and F444W) NIRCam imaging in the Spitzer IRAC Dark Field (IDF). The three epochs were six months apart and spanned the full duration of Cycle 1. As the IDF is in the JWST continuous viewing zone, we were able to design the observations such that the two modules of NIRCam, modules A and B, were flipped by 180° and completely overlapped each other’s footprints in alternate epochs. We were therefore able to directly compare the photometry of the same objects observed with different modules and detectors, and we found significant photometric residuals up to ∼0.05 mag in some detectors and filters, for the default version of the calibration files that we used (jwst_1039.pmap). Moreover, there are multiplicative gradients present in the data obtained in the two long-wavelength bands. The problem is less severe in the data reduced using the latest pmap (jwst_1130.pmap as of 2023 September), but it is still present, and is non-negligible. We provide a recipe to correct for this systematic effect to bring the two modules onto a more consistent calibration, to a photometric precision better than ∼0.02 mag.
詹姆斯-韦伯太空望远镜（JWST）GTO计划中的 "用于再电离和透镜科学的主要河外星系区域"（Prime Extragalactic Areas for Reionization and Lensing Science）获得了一组独特的NIRCam观测数据，使我们能够显著改进两个NIRCam模块的默认测光校准。这些观测包括在斯皮策 IRAC 暗场（IDF）中对 4 波段（F150W、F200W、F356W 和 F444W）NIRCam 成像的三个纪元。这三个时间相隔六个月，跨越了整个周期 1。由于 IDF 位于 JWST 的连续观测区内，我们在设计观测时将 NIRCam 的两个模块（模块 A 和模块 B）翻转 180°，在交替的时间段内彼此的足迹完全重叠。因此，我们可以直接比较使用不同模块和探测器观测到的同一天体的光度，我们发现，在我们使用的默认版本的校准文件（jwst_1039.pmap）中，某些探测器和滤光片的光度残差高达 ∼0.05 mag。此外，在两个长波段获得的数据中还存在乘法梯度。在使用最新 pmap（截至 9 月 2023 日的 jwst_1130.pmap）缩减的数据中，这个问题没有那么严重，但仍然存在，而且不可忽略。我们提供了一个校正这一系统性影响的方法，使两个模块的校准更加一致，光度精度优于 ∼ 0.02 马格。
{"title":"JWST’s PEARLS: Improved Flux Calibration for NIRCam","authors":"Zhiyuan Ma, Haojing Yan, Bangzheng Sun, Seth H. Cohen, Rolf A. Jansen, Jake Summers, Rogier A. Windhorst, Jordan C. J. D’Silva, Anton M. Koekemoer, Dan Coe, Christopher J. Conselice, Simon P. Driver, Brenda Frye, Norman A. Grogin, Madeline A. Marshall, Mario Nonino, Rafael Ortiz, Nor Pirzkal, Aaron Robotham, Russell E. Ryan, Christopher N. A. Willmer, Heidi B. Hammel, Stefanie N. Milam, Nathan J. Adams, Cheng Cheng, Nimish P. Hathi","doi":"10.1088/1538-3873/ad1f3e","DOIUrl":"https://doi.org/10.1088/1538-3873/ad1f3e","url":null,"abstract":"The Prime Extragalactic Areas for Reionization and Lensing Science, a James Webb Space Telescope (JWST) GTO program, obtained a set of unique NIRCam observations that have enabled us to significantly improve the default photometric calibration across both NIRCam modules. The observations consisted of three epochs of 4-band (F150W, F200W, F356W, and F444W) NIRCam imaging in the Spitzer IRAC Dark Field (IDF). The three epochs were six months apart and spanned the full duration of Cycle 1. As the IDF is in the JWST continuous viewing zone, we were able to design the observations such that the two modules of NIRCam, modules A and B, were flipped by 180° and completely overlapped each other’s footprints in alternate epochs. We were therefore able to directly compare the photometry of the same objects observed with different modules and detectors, and we found significant photometric residuals up to ∼0.05 mag in some detectors and filters, for the default version of the calibration files that we used (<monospace>jwst</monospace>_<monospace>1039.pmap</monospace>). Moreover, there are multiplicative gradients present in the data obtained in the two long-wavelength bands. The problem is less severe in the data reduced using the latest pmap (<monospace>jwst</monospace>_<monospace>1130.pmap</monospace> as of 2023 September), but it is still present, and is non-negligible. We provide a recipe to correct for this systematic effect to bring the two modules onto a more consistent calibration, to a photometric precision better than ∼0.02 mag.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139764545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-30DOI: 10.1088/1538-3873/ad1ba7
Pranav Nagarajan, Kareem El-Badry, Amaury H. M. J. Triaud, Thomas A. Baycroft, David Latham, Allyson Bieryla, Lars A. Buchhave, Hans-Walter Rix, Eliot Quataert, Andrew Howard, Howard Isaacson, Melissa J. Hobson
We present high-precision radial velocity observations of Gaia BH1, the nearest known black hole (BH). The system contains a solar-type G star orbiting a massive dark companion, which could be either a single BH or an inner BH + BH binary. A BH + BH binary is expected in some models where Gaia BH1 formed as a hierarchical triple, which is attractive because they avoid many of the difficulties associated with forming the system through isolated binary evolution. Our observations test the inner binary scenario. We have measured 115 precise RVs of the G star, including 40 from ESPRESSO with a precision of 3–5 m s−1, and 75 from other instruments with a typical precision of 30–100 m s−1. Our observations span 2.33 orbits of the G star and are concentrated near a periastron passage, when perturbations due to an inner binary would be largest. The RVs are well-fit by a Keplerian two-body orbit and show no convincing evidence of an inner binary. Using REBOUND simulations of hierarchical triples with a range of inner periods, mass ratios, eccentricities, and orientations, we show that plausible inner binaries with periods Pinner ≳ 1.5 days would have produced larger deviations from a Keplerian orbit than observed. Binaries with Pinner ≲ 1.5 days are consistent with the data, but these would merge within a Hubble time and would thus imply fine-tuning. We present updated parameters of Gaia BH1's orbit. The RVs yield a spectroscopic mass function fMBH=3.9358±0.0002M⊙—about 7000σ above the ∼2.5 M⊙ maximum neutron star mass. Including the inclination constraint from Gaia astrometry, this implies a BH mass of MBH = 9.27 ± 0.10 M⊙.
我们展示了对已知最近的黑洞 Gaia BH1 的高精度径向速度观测结果。该系统包含一颗太阳型G星，围绕着一颗大质量暗伴星运行，这颗伴星可能是单个黑洞，也可能是内部的黑洞+黑洞双星。在一些模型中，盖亚BH1会形成一个分层三重BH+BH双星，这很有吸引力，因为它们避免了通过孤立双星演化形成系统所带来的许多困难。我们的观测检验了内部双星的情况。我们测量了 G 星的 115 个精确 RV 值，其中 40 个来自 ESPRESSO，精度为 3-5 m s-1，75 个来自其他仪器，精度通常为 30-100 m s-1。我们的观测数据跨越了 G 星的 2.33 个轨道，并集中在近地轨道附近，此时内部双星造成的扰动最大。RV值与开普勒双体轨道拟合良好，没有显示出内部双星的令人信服的证据。我们利用REBOUND模拟了具有一系列内部周期、质量比、偏心率和方向的分级三体，结果表明周期Pinner ≳ 1.5天的可信内部双星会产生比观测到的更大的开普勒轨道偏差。Pinner≲1.5天的双星与数据一致，但这些双星会在哈勃时间内合并，因此意味着微调。我们给出了 Gaia BH1 轨道的最新参数。RVs得出的光谱质量函数fMBH=3.9358±0.0002M⊙-比∼2.5M⊙最大中子星质量高出约7000σ。包括来自盖亚天体测量的倾角约束，这意味着BH质量为MBH=9.27±0.10 M⊙。
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Pub Date : 2024-01-30DOI: 10.1088/1538-3873/ad1b36
Bernard J. Rauscher
NSClean is an algorithm and python package for removing faint vertical banding and “picture frame noise” from JWST Near Infrared Spectrograph (NIRSpec) images. NSClean uses known dark areas to fit a background model to each exposure in Fourier space. When the model is subtracted, it removes nearly all correlated noise. Compared to simpler strategies like subtracting the rolling median, NSClean is more thorough and uniform. NSClean has been developed and tested for NIRSpec IFU mode data, although it can be used on other NIRSpec modes as well. NSClean is computationally undemanding, requiring only a few seconds to clean an image on a typical laptop. The NSClean package is freely available from the NASA JWST website.
{"title":"NSClean: An Algorithm for Removing Correlated Noise from JWST NIRSpec Images","authors":"Bernard J. Rauscher","doi":"10.1088/1538-3873/ad1b36","DOIUrl":"https://doi.org/10.1088/1538-3873/ad1b36","url":null,"abstract":"NSClean is an algorithm and python package for removing faint vertical banding and “picture frame noise” from JWST Near Infrared Spectrograph (NIRSpec) images. NSClean uses known dark areas to fit a background model to each exposure in Fourier space. When the model is subtracted, it removes nearly all correlated noise. Compared to simpler strategies like subtracting the rolling median, NSClean is more thorough and uniform. NSClean has been developed and tested for NIRSpec IFU mode data, although it can be used on other NIRSpec modes as well. NSClean is computationally undemanding, requiring only a few seconds to clean an image on a typical laptop. The NSClean package is freely available from the NASA JWST website.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139764559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-22DOI: 10.1088/1538-3873/ad1412
Jason D. Eastman
We present a novel eccentricity parameterization for transit-only fits that allows us to efficiently sample the eccentricity and argument of periastron, while being able to generate a self-consistent model of a planet in a Keplerian orbit around its host star. With simulated fits of 330 randomly generated systems, we demonstrate that typical parameterizations often lead to inaccurate and overly precise determinations of the planetary eccentricity. However, our proposed parameterization allows us to accurately—and often precisely—recover the eccentricity for the simulated planetary systems with only transit data available.
{"title":"A Novel Eccentricity Parameterization for Transit-only Models","authors":"Jason D. Eastman","doi":"10.1088/1538-3873/ad1412","DOIUrl":"https://doi.org/10.1088/1538-3873/ad1412","url":null,"abstract":"We present a novel eccentricity parameterization for transit-only fits that allows us to efficiently sample the eccentricity and argument of periastron, while being able to generate a self-consistent model of a planet in a Keplerian orbit around its host star. With simulated fits of 330 randomly generated systems, we demonstrate that typical parameterizations often lead to inaccurate and overly precise determinations of the planetary eccentricity. However, our proposed parameterization allows us to accurately—and often precisely—recover the eccentricity for the simulated planetary systems with only transit data available.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139764447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-12DOI: 10.1088/1538-3873/ad0ca3
Mario L. Vicuña, Jorge F. Silva, Rene A. Mendez, Marcos E. Orchard, Sebastian Espinosa, Jeremy Tregloan-Reed
In this paper we study the joint determination of source and background flux for point sources as observed by digital array detectors. We explicitly compute the two-dimensional Cramér–Rao absolute lower bound (CRLB) as well as the performance bounds for high-dimensional implicit estimators from a generalized Taylor expansion. This later approach allows us to obtain computable prescriptions for the bias and variance of the joint estimators. We compare these prescriptions with empirical results from numerical simulations in the case of the weighted least squares estimator (introducing an improved version, denoted stochastic weighted least-squares) as well as with the maximum likelihood estimator, finding excellent agreement. We demonstrate that these estimators provide quasi-unbiased joint estimations of the flux and background, with a variance that approaches the CRLB very tightly and are, hence, optimal, unlike the case of sequential estimation used commonly in astronomical photometry which is sub-optimal. We compare our predictions with numerical simulations of realistic observations, as well as with observations of a bona fide non-variable stellar source observed with TESS, and compare it to the results from the sequential estimation of background and flux, confirming our theoretical expectations. Our practical estimators can be used as benchmarks for general photometric pipelines, or for applications that require maximum precision and accuracy in absolute photometry.
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Pub Date : 2024-01-01DOI: 10.1088/1538-3873/ad1b39
S. Tinyanont, R. J. Foley, K. Taggart, K. Davis, N. LeBaron, J. E. Andrews, M. J. Bustamante-Rosell, Y. Camacho-Neves, R. Chornock, D. Coulter, L. Galbany, S. Jha, C. Kilpatrick, L. Kwok, C. Larison, J. Pierel, M. Siebert, G. Aldering, K. Auchettl, J. S. Bloom, S. Dhawan, A. Filippenko, K. D. French, Alexander T Gagliano, M. Grayling, D. Howell, W. Jacobson-Galán, D. Jones, X. Le Saux, P. Macias, K. Mandel, C. McCully, E. Padilla Gonzalez, A. Rest, J. Rho, C. Rojas-Bravo, M. Skrutskie, S. Thorp, Q. Wang, S. M. Ward
We present the Keck Infrared Transient Survey, a NASA Key Strategic Mission Support program to obtain near-infrared (NIR) spectra of astrophysical transients of all types, and its first data release, consisting of 105 NIR spectra of 50 transients. Such a data set is essential as we enter a new era of IR astronomy with the James Webb Space Telescope (JWST) and the upcoming Nancy Grace Roman Space Telescope (Roman). NIR spectral templates will be essential to search JWST images for stellar explosions of the first stars and to plan an effective Roman SN Ia cosmology survey, both key science objectives for mission success. Between 2022 February and 2023 July, we systematically obtained 274 NIR spectra of 146 astronomical transients, representing a significant increase in the number of available NIR spectra in the literature. Here, we describe the first release of data from the 2022A semester. We systematically observed three samples: a flux-limited sample that includes all transients <17 mag in a red optical band (usually ZTF r or ATLAS o bands); a volume-limited sample including all transients within redshift z < 0.01 (D ≈ 50 Mpc); and an SN Ia sample targeting objects at phases and light-curve parameters that had scant existing NIR data in the literature. The flux-limited sample is 39% complete (60% excluding SNe Ia), while the volume-limited sample is 54% complete and is 79% complete to z = 0.005. Transient classes observed include common Type Ia and core-collapse supernovae, tidal disruption events, luminous red novae, and the newly categorized hydrogen-free/helium-poor interacting Type Icn supernovae. We describe our observing procedures and data reduction using PypeIt, which requires minimal human interaction to ensure reproducibility.
我们介绍了凯克红外瞬变巡天计划（Keck Infrared Transient Survey），这是美国国家航空航天局（NASA）的一项关键战略任务支持计划，旨在获取各类天体物理瞬变体的近红外（NIR）光谱，其首次发布的数据包括 50 个瞬变体的 105 个近红外光谱。随着詹姆斯-韦伯太空望远镜（JWST）和即将问世的南希-格蕾丝-罗曼太空望远镜（Roman）进入红外天文学的新时代，这样的数据集是必不可少的。近红外光谱模板对于搜索 JWST 图像中第一颗恒星的恒星爆炸和规划有效的 Roman SN Ia 宇宙学调查至关重要，这两项都是任务成功的关键科学目标。从 2022 年 2 月到 2023 年 7 月，我们系统地获得了 146 个天文瞬变体的 274 个近红外光谱，这意味着文献中可用的近红外光谱数量有了显著增加。在此，我们将介绍 2022A 星期首次发布的数据。我们系统地观测了三个样本：通量限制样本，包括红光波段（通常是 ZTF r 波段或 ATLAS o 波段）中小于 17 马格的所有瞬变天体；体积限制样本，包括红移 z < 0.01（D ≈ 50 Mpc）范围内的所有瞬变天体；以及 SN Ia 样本，其目标天体的相位和光变曲线参数在文献中的现有近红外数据很少。通量限制样本完成了39%（60%不包括SNe Ia），体积限制样本完成了54%，z = 0.005时完成了79%。观测到的瞬态类别包括常见的Ia型和核心坍缩超新星、潮汐破坏事件、发光红色新星以及新分类的无氢/贫氦相互作用Icn型超新星。我们介绍了我们的观测程序和使用PypeIt进行的数据还原，它只需要极少的人工互动，以确保可重复性。
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Pub Date : 2023-12-28DOI: 10.1088/1538-3873/acff85
S. R. Kulkarni, J. Michael Shull
The Galactic interstellar medium abounds in shocks with low velocities vs ≲ 70 km s−1. Some are descendants of higher velocity shocks, while others start off at low velocity (e.g., stellar bow shocks, intermediate velocity clouds, spiral density waves). Low-velocity shocks cool primarily via Lyα and two-photon continuum, augmented by optical recombination lines (e.g., Hα), forbidden lines of metals and free-bound emission, free–free emission. The dark far-ultraviolet (FUV) sky, aided by the fact that the two-photon continuum peaks at 1400 Å, makes the FUV band an ideal tracer of low-velocity shocks. GALEX FUV images reaffirm this expectation, discovering faint and large interstellar structure in old supernova remnants and thin arcs stretching across the sky. Interstellar bow shocks are expected from fast stars from the Galactic disk passing through the numerous gas clouds in the local interstellar medium within 15 pc of the Sun. Using the bests atomic data available to date, we present convenient fitting formulae for yields of Lyα, two-photon continuum, and Hα for pure hydrogen plasma in the temperature range of 104–105 K. The formulae presented here can be readily incorporated into time-dependent cooling models as well as collisional ionization equilibrium models.
银河系星际介质中存在大量低速 vs ≲ 70 km s-1 的冲击波。有些是高速冲击波的后代，有些则是从低速冲击波开始的（如恒星弓形冲击波、中速云、螺旋密度波）。低速冲击主要通过 Lyα 和双光子连续波来冷却，并通过光学重组线（如 Hα）、金属禁线和自由束缚发射、自由发射来增强。暗色的远紫外（FUV）天空，加上双光子连续波在 1400 Å 处达到峰值，使得 FUV 波段成为低速冲击的理想示踪波段。GALEX 的 FUV 图像再次证实了这一预期，在古老的超新星遗迹和延伸至整个天空的细弧中发现了微弱而巨大的星际结构。星际弓形冲击预计是来自银河盘的快速恒星穿过太阳周围 15 pc 范围内的本地星际介质中的大量气体云时产生的。利用迄今为止最好的原子数据，我们提出了温度范围在 104-105 K 的纯氢等离子体的 Lyα、双光子连续光和 Hα 产量的便捷拟合公式。
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Pub Date : 2023-12-21DOI: 10.1088/1538-3873/ad0d7b
Amy M. Jones, Rachael L. Beaton, Brian A. Cherinka, Karen L. Masters, Sara Lucatello, Aleksandar M. Diamond-Stanic, Sarah A. Bird, Michael R. Blanton, Katia Cunha, Emily E. Farr, Diane Feuillet, Peter M. Frinchaboy, Alex Hagen, Karen Kinemuchi, Britt Lundgren, Mariarosa L. Marinelli, Adam D. Myers, Alexandre Roman-Lopes, Ashley J. Ross, José R. Sánchez-Gallego, Sarah J. Schmidt, Jennifer Sobeck, Keivan G. Stassun, Jamie Tayar, Mariana Vargas-Magaña, J. C. Wilson, Gail Zasowski
The Sloan Digital Sky Survey (SDSS) is one of the largest international astronomy organizations. We present demographic data based on surveys of its members from 2014, 2015 and 2016, during the fourth phase of SDSS (SDSS-IV). We find about half of SDSS-IV collaboration members were based in North America, a quarter in Europe, and the remainder in Asia and Central and South America. Overall, 26%–36% are women (from 2014 to 2016), up to 2% report non-binary genders. 11%–14% report that they are racial or ethnic minorities where they live. The fraction of women drops with seniority, and is also lower among collaboration leadership. Men in SDSS-IV were more likely to report being in a leadership role, and for the role to be funded and formally recognized. SDSS-IV collaboration members are twice as likely to have a parent with a college degree, than the general population, and are ten times more likely to have a parent with a PhD. This trend is slightly enhanced for female collaboration members. Despite this, the fraction of first generation college students is significant (31%). This fraction increased among collaboration members who are racial or ethnic minorities (40%–50%), and decreased among women (15%–25%). SDSS-IV implemented many inclusive policies and established a dedicated committee, the Committee on INclusiveness in SDSS. More than 60% of the collaboration agree that the collaboration is inclusive; however, collaboration leadership more strongly agree with this than the general membership. In this paper, we explain these results in full, including the history of inclusive efforts in SDSS-IV. We conclude with a list of suggested recommendations based on our findings, which can be used to improve equity and inclusion in large astronomical collaborations, which we argue is not only moral, but will also optimize their scientific output.
{"title":"SDSS-IV from 2014 to 2016: A Detailed Demographic Comparison over Three Years","authors":"Amy M. Jones, Rachael L. Beaton, Brian A. Cherinka, Karen L. Masters, Sara Lucatello, Aleksandar M. Diamond-Stanic, Sarah A. Bird, Michael R. Blanton, Katia Cunha, Emily E. Farr, Diane Feuillet, Peter M. Frinchaboy, Alex Hagen, Karen Kinemuchi, Britt Lundgren, Mariarosa L. Marinelli, Adam D. Myers, Alexandre Roman-Lopes, Ashley J. Ross, José R. Sánchez-Gallego, Sarah J. Schmidt, Jennifer Sobeck, Keivan G. Stassun, Jamie Tayar, Mariana Vargas-Magaña, J. C. Wilson, Gail Zasowski","doi":"10.1088/1538-3873/ad0d7b","DOIUrl":"https://doi.org/10.1088/1538-3873/ad0d7b","url":null,"abstract":"The Sloan Digital Sky Survey (SDSS) is one of the largest international astronomy organizations. We present demographic data based on surveys of its members from 2014, 2015 and 2016, during the fourth phase of SDSS (SDSS-IV). We find about half of SDSS-IV collaboration members were based in North America, a quarter in Europe, and the remainder in Asia and Central and South America. Overall, 26%–36% are women (from 2014 to 2016), up to 2% report non-binary genders. 11%–14% report that they are racial or ethnic minorities where they live. The fraction of women drops with seniority, and is also lower among collaboration leadership. Men in SDSS-IV were more likely to report being in a leadership role, and for the role to be funded and formally recognized. SDSS-IV collaboration members are twice as likely to have a parent with a college degree, than the general population, and are ten times more likely to have a parent with a PhD. This trend is slightly enhanced for female collaboration members. Despite this, the fraction of first generation college students is significant (31%). This fraction increased among collaboration members who are racial or ethnic minorities (40%–50%), and decreased among women (15%–25%). SDSS-IV implemented many inclusive policies and established a dedicated committee, the Committee on INclusiveness in SDSS. More than 60% of the collaboration agree that the collaboration is inclusive; however, collaboration leadership more strongly agree with this than the general membership. In this paper, we explain these results in full, including the history of inclusive efforts in SDSS-IV. We conclude with a list of suggested recommendations based on our findings, which can be used to improve equity and inclusion in large astronomical collaborations, which we argue is not only moral, but will also optimize their scientific output.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139053449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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