Pub Date : 2024-09-09DOI: 10.3847/1538-4365/ad67d5
Hongwei Xi, Bo Peng, Lister Staveley-Smith, Bi-Qing For, Bin Liu and Dejian Ding
We have used the Five-hundred-meter Aperture Spherical radio Telescope (FAST) to conduct a blind ultradeep survey for neutral hydrogen (H i). We present the complete results from the first of six fields (FUDS0). These observations of 95 hr allowed us to achieve a high-sensitivity (∼50 μJy beam−1) and a high-frequency resolution (22.9 kHz) over an area of 0.72 deg2. We detected 128 galaxies in H i distributed over the redshift range of 0 < z < 0.4, with H i masses in the range of , and three faint high-velocity clouds, with a peak column density of NH i ≤ 3.1 × 1017 cm−2. Of the galaxies, 95 are new detections and six have z > 0.38, where no unlensed H i emission has previously been directly detected. Estimates of completeness and reliability are presented for the catalog. The consistency of continuum and H i flux estimates with the NRAO VLA Sky Survey and the Arecibo Ultra-Deep Survey, respectively, confirms the accuracy of the calibration method and data reduction pipeline developed for the full FAST Ultra-Deep Survey.
我们利用五百米孔径球面射电望远镜(FAST)对中性氢(H i)进行了一次超深度盲观测。我们展示了六个观测场(FUDS0)中第一个观测场的完整结果。这些长达 95 小时的观测使我们在 0.72 平方英寸的区域内达到了高灵敏度(∼50 μJy beam-1)和高频分辨率(22.9 kHz)。我们探测到了128个H i星系,它们分布在0 < z < 0.4的红移范围内,H i质量在 ,以及三个微弱的高速云,峰值柱密度为NH i ≤ 3.1 × 1017 cm-2。在这些星系中,有 95 个是新探测到的,6 个星系的 z 值大于 0.38,在这些星系中,以前没有直接探测到过非凝聚 H i 辐射。对星表的完整性和可靠性进行了估计。连续波和 H i 通量的估计值分别与 NRAO VLA 巡天和阿雷西博超深巡天保持一致,这证实了为整个 FAST 超深巡天开发的校准方法和数据缩减管道的准确性。
{"title":"FAST Ultra-Deep Survey: Data Release for FUDS0","authors":"Hongwei Xi, Bo Peng, Lister Staveley-Smith, Bi-Qing For, Bin Liu and Dejian Ding","doi":"10.3847/1538-4365/ad67d5","DOIUrl":"https://doi.org/10.3847/1538-4365/ad67d5","url":null,"abstract":"We have used the Five-hundred-meter Aperture Spherical radio Telescope (FAST) to conduct a blind ultradeep survey for neutral hydrogen (H i). We present the complete results from the first of six fields (FUDS0). These observations of 95 hr allowed us to achieve a high-sensitivity (∼50 μJy beam−1) and a high-frequency resolution (22.9 kHz) over an area of 0.72 deg2. We detected 128 galaxies in H i distributed over the redshift range of 0 < z < 0.4, with H i masses in the range of , and three faint high-velocity clouds, with a peak column density of NH i ≤ 3.1 × 1017 cm−2. Of the galaxies, 95 are new detections and six have z > 0.38, where no unlensed H i emission has previously been directly detected. Estimates of completeness and reliability are presented for the catalog. The consistency of continuum and H i flux estimates with the NRAO VLA Sky Survey and the Arecibo Ultra-Deep Survey, respectively, confirms the accuracy of the calibration method and data reduction pipeline developed for the full FAST Ultra-Deep Survey.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142187535","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 : 2024-09-09DOI: 10.3847/1538-4365/ad527e
C. Storfer, X. Huang, A. Gu, W. Sheu, S. Banka, A. Dey, J. Inchausti Reyes, A. Jain, K. J. Kwon, D. Lang, V. Lee, A. Meisner, J. Moustakas, A. D. Myers, S. Tabares-Tarquinio, E. F. Schlafly, D. J. Schlegel
We have conducted a search for strong gravitational lensing systems in the Dark Energy Spectroscopic Instrument (DESI) Legacy Imaging Surveys Data Release 9. This is the third paper in a series. These surveys together cover ∼19,000 deg2 visible from the Northern Hemisphere, reaching a z-band AB magnitude of ∼22.5. We use a deep residual neural network, trained on a compilation of known lensing systems and high-grade candidates as well as nonlenses in the same footprint. After applying our trained neural network to the survey data, we visually inspect and rank images with probabilities above a threshold which has been chosen to balance precision and recall. We have found 1895 lens candidates, of which 1512 are identified for the first time. Combining the discoveries from this work with those from Papers I (335) and II (1210), we have discovered a total of 3057 new candidates in the Legacy Surveys.
{"title":"New Strong Gravitational Lenses from the DESI Legacy Imaging Surveys Data Release 9","authors":"C. Storfer, X. Huang, A. Gu, W. Sheu, S. Banka, A. Dey, J. Inchausti Reyes, A. Jain, K. J. Kwon, D. Lang, V. Lee, A. Meisner, J. Moustakas, A. D. Myers, S. Tabares-Tarquinio, E. F. Schlafly, D. J. Schlegel","doi":"10.3847/1538-4365/ad527e","DOIUrl":"https://doi.org/10.3847/1538-4365/ad527e","url":null,"abstract":"We have conducted a search for strong gravitational lensing systems in the Dark Energy Spectroscopic Instrument (DESI) Legacy Imaging Surveys Data Release 9. This is the third paper in a series. These surveys together cover ∼19,000 deg<sup>2</sup> visible from the Northern Hemisphere, reaching a <italic toggle=\"yes\">z</italic>-band AB magnitude of ∼22.5. We use a deep residual neural network, trained on a compilation of known lensing systems and high-grade candidates as well as nonlenses in the same footprint. After applying our trained neural network to the survey data, we visually inspect and rank images with probabilities above a threshold which has been chosen to balance precision and recall. We have found 1895 lens candidates, of which 1512 are identified for the first time. Combining the discoveries from this work with those from Papers I (335) and II (1210), we have discovered a total of 3057 new candidates in the Legacy Surveys.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"94 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142187536","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 : 2024-09-09DOI: 10.3847/1538-4365/ad5dac
Alessandro Maselli, William R. Forman, Christine Jones, Ralph P. Kraft, Matteo Perri
Based on a proposal to observe 18 bright radio sources from the SMS4 catalog with the Neil Gehrels Swift Observatory (hereafter Swift), we obtained X-ray observations of 17 targets (one target was not observed). Following up our first paper that discussed 31 sources (see Maselli et al.; 20 sources detected as point sources and one very extended source), we present results for this final sample of 17 radio sources that previously lacked dedicated, pointed narrow-field-of-view (FOV) X-ray observations. One of these 17 sources, undetected by Swift due to a very short exposure, was instead detected by eROSITA, and given in the Data Release 1 (DR1) Catalog. No 1eRASS source was found in the DR1 for the remaining source, unobserved by Swift. The new Swift observations led to 11 X-ray source detections in the 0.3–10 keV band and six upper limits. We investigated the extent of the X-ray emission and the hardness ratio, and when statistics allowed, we carried out a spectral analysis. The X-ray emission of eight sources is consistent with pointlike emission, while three sources show clear evidence of extent, each with peculiar properties. We used the X-ray determined positions and uncertainties of the 12 detected sources to establish associations with infrared and optical sources from the AllWISE and the GSC 2.4.2 catalogs. Requiring a detection in both the infrared and the optical bands to establish a candidate counterpart for our X-ray detections, we identify counterparts for all 12 sources. Following this X-ray-based approach to derive the position of the active nucleus, we are able to confirm the same IR counterparts previously proposed by White et al. for eight sources, and provide four new IR candidates. In the optical, we identify counterparts that match the candidates previously given by Burgess & Hunstead for all sources. We discuss the interesting structure of MRC B0344−345 and PKS B2148−555, two of the six extended X-ray sources that we detected in both our Swift campaigns, and suggest they are very promising for further X-ray and radio investigations. For the 38 SMS4 sources that lack pointed, narrow-FOV X-ray telescope observations, after our Swift campaigns, we list 18 likely counterparts from the eROSITA DR1 catalog.
根据利用 Neil Gehrels Swift 天文台(以下简称 Swift)观测 SMS4 星表中 18 个明亮射电源的提议,我们获得了 17 个目标的 X 射线观测结果(一个目标未观测到)。我们的第一篇论文讨论了 31 个射电源(见 Maselli 等;20 个作为点源探测到的射电源和一个非常扩展的射电源),在这篇论文之后,我们将介绍这 17 个射电源的最终样本的结果,这些射电源以前缺乏专门的尖头窄视场 (FOV) X 射线观测。在这 17 个射电源中,有一个由于曝光时间很短而没有被 Swift 探测到,但却被 eROSITA 探测到,并被列入数据发布 1 (DR1) 目录。其余未被斯威夫特观测到的源在 DR1 中没有发现 1eRASS 源。新的 Swift 观测结果在 0.3-10 keV 波段发现了 11 个 X 射线源,并给出了 6 个上限。我们研究了 X 射线辐射的范围和硬度比,并在统计数据允许的情况下进行了光谱分析。8 个源的 X 射线辐射与点状辐射一致,而 3 个源则显示出明显的范围,每个源都具有奇特的性质。我们利用 X 射线确定的 12 个探测到的光源的位置和不确定性,与 AllWISE 和 GSC 2.4.2 星表中的红外线和光学光源建立了联系。由于需要同时在红外波段和光学波段进行探测,才能为我们的 X 射线探测建立候选对应体,因此我们为所有 12 个源找到了对应体。按照这种基于 X 射线的方法来推算活动核的位置,我们能够确认怀特等人之前为 8 个源提出的红外对应体,并提供了 4 个新的红外候选体。在光学方面,我们确定的对应天体与 Burgess & Hunstead 以前为所有天体提出的候选天体相吻合。我们讨论了 MRC B0344-345 和 PKS B2148-555 的有趣结构,它们是我们在两次 Swift 活动中都探测到的六个扩展 X 射线源中的两个,并建议对它们进行进一步的 X 射线和无线电研究。对于SMS4中的38个源,我们列出了eROSITA DR1星表中可能存在的18个对应天体。
{"title":"A Swift X-Ray View of the SMS4 Sample. II. X-Ray Properties of 17 Bright Radio Sources","authors":"Alessandro Maselli, William R. Forman, Christine Jones, Ralph P. Kraft, Matteo Perri","doi":"10.3847/1538-4365/ad5dac","DOIUrl":"https://doi.org/10.3847/1538-4365/ad5dac","url":null,"abstract":"Based on a proposal to observe 18 bright radio sources from the SMS4 catalog with the Neil Gehrels Swift Observatory (hereafter Swift), we obtained X-ray observations of 17 targets (one target was not observed). Following up our first paper that discussed 31 sources (see Maselli et al.; 20 sources detected as point sources and one very extended source), we present results for this final sample of 17 radio sources that previously lacked dedicated, pointed narrow-field-of-view (FOV) X-ray observations. One of these 17 sources, undetected by Swift due to a very short exposure, was instead detected by eROSITA, and given in the Data Release 1 (DR1) Catalog. No 1eRASS source was found in the DR1 for the remaining source, unobserved by Swift. The new Swift observations led to 11 X-ray source detections in the 0.3–10 keV band and six upper limits. We investigated the extent of the X-ray emission and the hardness ratio, and when statistics allowed, we carried out a spectral analysis. The X-ray emission of eight sources is consistent with pointlike emission, while three sources show clear evidence of extent, each with peculiar properties. We used the X-ray determined positions and uncertainties of the 12 detected sources to establish associations with infrared and optical sources from the AllWISE and the GSC 2.4.2 catalogs. Requiring a detection in both the infrared and the optical bands to establish a candidate counterpart for our X-ray detections, we identify counterparts for all 12 sources. Following this X-ray-based approach to derive the position of the active nucleus, we are able to confirm the same IR counterparts previously proposed by White et al. for eight sources, and provide four new IR candidates. In the optical, we identify counterparts that match the candidates previously given by Burgess & Hunstead for all sources. We discuss the interesting structure of MRC B0344−345 and PKS B2148−555, two of the six extended X-ray sources that we detected in both our Swift campaigns, and suggest they are very promising for further X-ray and radio investigations. For the 38 SMS4 sources that lack pointed, narrow-FOV X-ray telescope observations, after our Swift campaigns, we list 18 likely counterparts from the eROSITA DR1 catalog.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142187537","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}
The overall temporal and spectral characteristics (e.g., duration, fluence, peak flux, peak count rate, and total counts) of X-ray bursts (XRBs) originating from magnetars have been extensively studied to confirm their self-organized criticality (SOC) behaviors. However, for the pulses in XRBs, which are an important part of unraveling radiation processes such as magnetic reconnection and crustal rupture, their variable statistical characteristics are still unclear. In this work, we investigate the distributions of fluctuations in duration, waiting time, peak count rate, and total counts of pulses within bursts from two active and prolific magnetars, SGR J1935+2154 and SGR J1550-5418, observed by Fermi’s Gamma-ray Burst Monitor, Insight-HXMT, and GECAM. We report that the waiting time for pulses follows SOC, whereas previous studies indicated for bursts do not, possibly due to incomplete observations. Besides, the duration, peak count rate, and total counts for pulses are also SOC behaviors. The α-values for the duration of pulses for both magnetars are ∼2, and the inferred Euclidean dimension S is 3. Our findings provide evidence for the SOC of each radiation process during a burst, for example, multiple pulses produced by multiple magnetic reconnections triggered by a single starquake. Finally, the similar statistical characteristics for pulses from both magnetars lend support to their shared radiation processes.
{"title":"The Self-organized Criticality Behaviors of Pulses in Magnetar Bursts","authors":"Shuo Xiao, Mei-Xin Hong, Zi-Yi You, Tong-Lei Liao, Shao-Lin Xiong, Shu-Xu Yi, Ping Wang, Jiao-Jiao Yang, Zheng-Huo Jiang, Yue Wang, Yan-Qiu Zhang, Ming-Yu Ge, Zhen Zhang, Xi-Hong Luo, Shi-Jun Dang, Ru-shuang Zhao, Ai-Jun Dong, Qi-Jun Zhi, He Gao, Di Li, Shuang-Nan Zhang","doi":"10.3847/1538-4365/ad6b18","DOIUrl":"https://doi.org/10.3847/1538-4365/ad6b18","url":null,"abstract":"The overall temporal and spectral characteristics (e.g., duration, fluence, peak flux, peak count rate, and total counts) of X-ray bursts (XRBs) originating from magnetars have been extensively studied to confirm their self-organized criticality (SOC) behaviors. However, for the pulses in XRBs, which are an important part of unraveling radiation processes such as magnetic reconnection and crustal rupture, their variable statistical characteristics are still unclear. In this work, we investigate the distributions of fluctuations in duration, waiting time, peak count rate, and total counts of pulses within bursts from two active and prolific magnetars, SGR J1935+2154 and SGR J1550-5418, observed by Fermi’s Gamma-ray Burst Monitor, Insight-HXMT, and GECAM. We report that the waiting time for pulses follows SOC, whereas previous studies indicated for bursts do not, possibly due to incomplete observations. Besides, the duration, peak count rate, and total counts for pulses are also SOC behaviors. The <italic toggle=\"yes\">α</italic>-values for the duration of pulses for both magnetars are ∼2, and the inferred Euclidean dimension <italic toggle=\"yes\">S</italic> is 3. Our findings provide evidence for the SOC of each radiation process during a burst, for example, multiple pulses produced by multiple magnetic reconnections triggered by a single starquake. Finally, the similar statistical characteristics for pulses from both magnetars lend support to their shared radiation processes.","PeriodicalId":22368,"journal":{"name":"The Astrophysical Journal Supplement Series","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142187540","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 : 2024-09-04DOI: 10.3847/1538-4365/ad61e6
Roberto Galván-Madrid, Daniel J. Díaz-González, Frédérique Motte, Adam Ginsburg, Nichol Cunningham, Karl M. Menten, Mélanie Armante, Mélisse Bonfand, Jonathan Braine, Timea Csengeri, Pierre Dell’Ova, Fabien Louvet, Thomas Nony, Rudy Rivera-Soto, Patricio Sanhueza, Amelia M. Stutz, Friedrich Wyrowski, Rodrigo H. Álvarez-Gutiérrez, Tapas Baug, Sylvain Bontemps, Leonardo Bronfman, Manuel Fernández-López, Antoine Gusdorf, Atanu Koley, Hong-Li Liu, Javiera Salinas, Allison P. M. Towner, Anthony P. Whitworth
We use the H41α recombination line to create templates of the millimeter free–free emission in the ALMA-IMF continuum maps, which allows us to separate it from dust emission. This method complements spectral-index information and extrapolation from centimeter-wavelength maps. We use the derived maps to estimate the properties of up to 34 H ii regions across the ALMA-IMF protoclusters. The hydrogen ionizing photon rate Q