Publications of the Astronomical Society of the Pacific最新文献

筛选
英文 中文
SPECtrophotometer for TRansmission Spectroscopy of Exoplanets (SPECTR) 系外行星透射光谱 SPECtrophotometer(SPECTR)
IF 3.5 3区 物理与天体物理
Publications of the Astronomical Society of the Pacific Pub Date : 2024-08-20 DOI: 10.1088/1538-3873/ad692d
Yeon-Ho Choi, Myeong-Gu Park, Kang-Min Kim, Jae-Rim Koo, Tae-Yang Bang, Chan Park, Jeong-Gyun Jang, Inwoo Han, Bi-Ho Jang, Jong Ung Lee, Ueejeong Jeong, Byeong-Cheol Lee
{"title":"SPECtrophotometer for TRansmission Spectroscopy of Exoplanets (SPECTR)","authors":"Yeon-Ho Choi, Myeong-Gu Park, Kang-Min Kim, Jae-Rim Koo, Tae-Yang Bang, Chan Park, Jeong-Gyun Jang, Inwoo Han, Bi-Ho Jang, Jong Ung Lee, Ueejeong Jeong, Byeong-Cheol Lee","doi":"10.1088/1538-3873/ad692d","DOIUrl":"https://doi.org/10.1088/1538-3873/ad692d","url":null,"abstract":"The SPECtrophotometer for TRansmission spectroscopy of exoplanets (SPECTR) is a new low-resolution optical (3800–6850 Å) spectrophotometer installed at the Bohyunsan Optical Astronomy Observatory 1.8 m telescope. SPECTR is designed for observing the transmission spectra of transiting exoplanets. Unique features of SPECTR are its long slit length of 10′ which facilitates observing the target and the comparison star simultaneously, and its wide slit width to minimize slit losses. SPECTR will be used to survey exoplanets, such as those identified by the Transiting Exoplanet Survey Satellite, providing information about their radii across the wavelength range. In this paper, we present the design of SPECTR and the observational results of the partial transit of HD 189733 b and a full transit of Qatar-8 b. Analyses show the SPECTR’s capability on the white light curves with an accuracy of one ppt. The transmission spectrum of HD 189733 b shows general agreement with previous studies.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142183190","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}
引用次数: 0
An Automated Catalog of Long Period Variables using Infrared Lightcurves from Palomar Gattini-IR 利用帕洛玛-加蒂尼-红外光谱的红外光曲线自动编制长周期变星表
IF 3.5 3区 物理与天体物理
Publications of the Astronomical Society of the Pacific Pub Date : 2024-08-20 DOI: 10.1088/1538-3873/ad68a4
Aswin Suresh, Viraj Karambelkar, Mansi M. Kasliwal, Michael C. B. Ashley, Kishalay De, Matthew J. Hankins, Anna M. Moore, Jamie Soon, Roberto Soria, Tony Travouillon, Kayton K. Truong
{"title":"An Automated Catalog of Long Period Variables using Infrared Lightcurves from Palomar Gattini-IR","authors":"Aswin Suresh, Viraj Karambelkar, Mansi M. Kasliwal, Michael C. B. Ashley, Kishalay De, Matthew J. Hankins, Anna M. Moore, Jamie Soon, Roberto Soria, Tony Travouillon, Kayton K. Truong","doi":"10.1088/1538-3873/ad68a4","DOIUrl":"https://doi.org/10.1088/1538-3873/ad68a4","url":null,"abstract":"Long Period Variables (LPVs) are stars with periods of several hundred days, representing the late, dust-enshrouded phase of stellar evolution in low to intermediate mass stars. In this paper, we present a catalog of 154,755 LPVs using near-IR lightcurves from the Palomar Gattini-IR (PGIR) survey. PGIR has been surveying the entire accessible northern sky (<italic toggle=\"yes\">δ</italic> &gt; −28°) in the <italic toggle=\"yes\">J</italic>-band at a cadence of 2–3 days since 2018 September, and has produced <italic toggle=\"yes\">J</italic>-band lightcurves for more than 60 million sources. We used a gradient-boosted decision tree classifier trained on a comprehensive feature set extracted from PGIR lightcurves to search for LPVs in this data set. We developed a parallelized and optimized code to extract features at a rate of ∼0.1 s per lightcurve. Our model can successfully distinguish LPVs from other stars with a true positive rate of 95%. Cross-matching with known LPVs, we find 70,369 (∼46%) new LPVs in our catalog.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142183189","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}
引用次数: 0
Enhancing GWOPS Capabilities for Coordinated Multi-Telescope Detection of Gravitational Wave Electromagnetic Counterparts 增强 GWOPS 协调多望远镜探测引力波电磁对应体的能力
IF 3.5 3区 物理与天体物理
Publications of the Astronomical Society of the Pacific Pub Date : 2024-08-20 DOI: 10.1088/1538-3873/ad6710
Penghui Ma, Yunfei Xu, Jingwei Hu, Zhen Zhang, Liang Ge, Min He, Shanshan Li, Linying Mi, Changhua Li, Dongwei Fan, Chenzhou Cui
{"title":"Enhancing GWOPS Capabilities for Coordinated Multi-Telescope Detection of Gravitational Wave Electromagnetic Counterparts","authors":"Penghui Ma, Yunfei Xu, Jingwei Hu, Zhen Zhang, Liang Ge, Min He, Shanshan Li, Linying Mi, Changhua Li, Dongwei Fan, Chenzhou Cui","doi":"10.1088/1538-3873/ad6710","DOIUrl":"https://doi.org/10.1088/1538-3873/ad6710","url":null,"abstract":"The groundbreaking detection of gravitational waves (GWs) has ushered in a new era of astronomical observation, granting us access to cosmic phenomena that are imperceptible to electromagnetic waves. The inherently weak GW signals coupled with the substantial uncertainties in source localization pose significant challenges to the field of astronomy. In this paper, we introduce innovative strategies to enhance the efficiency of observing electromagnetic counterparts to GW events, thereby unlocking further secrets of the cosmos. We present a novel technique for designing observation targets and establishing priorities, progressing from the epicenter to the periphery within the boundaries of the GW error sky region. This method has significantly reduced the average slewing distance of telescopes by 41% compared to traditional methods, thus enhancing observational efficiency. Additionally, we have developed a collaborative observation strategy for telescope networks, allocating observation targets based on the field-of-view (FOV) sizes of individual telescopes. This ensures comprehensive coverage without redundancy, allowing a network of four telescopes to cover a sky area and accumulate observation probability more than four times that of a single telescope operating independently over an equivalent period. Building upon these strategies, we have significantly upgraded GWOPS, the GW Follow-up Observation Planning System developed by the China-VO team, to provide precise observational planning for large FOV (greater than 1 square degree) telescope networks. The system also features a web-based user interface that presents the GW error sky area and observation planning results in a graphical format, significantly improving user interaction and experience. The research presented herein equips astronomers with a robust toolkit, advancing the efficiency of searching for and studying electromagnetic counterparts to GW events, and heralding new frontiers in the research of astrophysics and cosmology.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142183191","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}
引用次数: 0
Wide Post-common Envelope Binaries from Gaia: Orbit Validation and Formation Models 来自盖亚的宽后共同包络双星:轨道验证和形成模型
IF 3.5 3区 物理与天体物理
Publications of the Astronomical Society of the Pacific Pub Date : 2024-08-12 DOI: 10.1088/1538-3873/ad6809
Natsuko Yamaguchi, Kareem El-Badry, Natalie R. Rees, Sahar Shahaf, Tsevi Mazeh, Renŕ Andrae
{"title":"Wide Post-common Envelope Binaries from Gaia: Orbit Validation and Formation Models","authors":"Natsuko Yamaguchi, Kareem El-Badry, Natalie R. Rees, Sahar Shahaf, Tsevi Mazeh, Renŕ Andrae","doi":"10.1088/1538-3873/ad6809","DOIUrl":"https://doi.org/10.1088/1538-3873/ad6809","url":null,"abstract":"Astrometry from Gaia DR3 has enabled the discovery of a sample of 3000+ binaries containing white dwarfs (WD) and main-sequence (MS) stars in relatively wide orbits, with orbital periods <italic toggle=\"yes\">P</italic>\u0000<sub>orb</sub> = (100–1000) days. This population was not predicted by binary population synthesis models before Gaia and—if the Gaia orbits are robust—likely requires very efficient envelope ejection during common envelope evolution (CEE). To assess the reliability of the Gaia solutions, we measured multi-epoch radial velocities (RVs) of 31 WD+MS binary candidates with <italic toggle=\"yes\">P</italic>\u0000<sub>orb</sub> = (40–300) days and <monospace>AstroSpectroSB1</monospace> orbital solutions. We jointly fit the RVs and astrometry, allowing us to validate the Gaia solutions and tighten constraints on component masses. We find a high success rate for the Gaia solutions, with only 2 out of the 31 systems showing significant discrepancies between their Gaia orbital solutions and our RVs. Joint fitting of RVs and astrometry allows us to directly constrain the secondary-to-primary flux ratio <inline-formula>\u0000<tex-math>\u0000<?CDATA ${ mathcal S }$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mi mathvariant=\"script\">S</mml:mi></mml:math>\u0000<inline-graphic xlink:href=\"paspad6809ieqn1.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula>, and we find <inline-formula>\u0000<tex-math>\u0000<?CDATA ${ mathcal S }lesssim 0.02$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mi mathvariant=\"script\">S</mml:mi><mml:mo>≲</mml:mo><mml:mn>0.02</mml:mn></mml:math>\u0000<inline-graphic xlink:href=\"paspad6809ieqn2.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> for most objects, confirming the companions are indeed WDs. We tighten constraints on the binaries’ eccentricities, finding a median <italic toggle=\"yes\">e</italic> ≈ 0.1. These eccentricities are much lower than those of normal MS+MS binaries at similar periods, but much higher than predicted for binaries formed via stable mass transfer. We present MESA single and binary evolution models to explore how the binaries may have formed. The orbits of most binaries in the sample can be produced through CEE that begins when the WD progenitor is an AGB star, corresponding to initial separations of 2–5 au. Roughly 50% of all post-common envelope binaries are predicted to have first interacted on the AGB, ending up in wide orbits like these systems.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142183193","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}
引用次数: 0
Toward Exoplanet Transit Spectroscopy Using JWST/MIRI’s Medium Resolution Spectrometer 利用 JWST/MIRI 的中分辨率分光计开展系外行星凌日分光研究
IF 3.5 3区 物理与天体物理
Publications of the Astronomical Society of the Pacific Pub Date : 2024-08-08 DOI: 10.1088/1538-3873/ad6692
Drake Deming, Guangwei Fu, Jeroen Bouwman, Daniel Dicken, Nestor Espinoza, Alistair Glasse, Thomas Greene, Sarah Kendrew, David Law, Jacob Lustig-Yaeger, Macarena Garcia Marin and Everett Schlawin
{"title":"Toward Exoplanet Transit Spectroscopy Using JWST/MIRI’s Medium Resolution Spectrometer","authors":"Drake Deming, Guangwei Fu, Jeroen Bouwman, Daniel Dicken, Nestor Espinoza, Alistair Glasse, Thomas Greene, Sarah Kendrew, David Law, Jacob Lustig-Yaeger, Macarena Garcia Marin and Everett Schlawin","doi":"10.1088/1538-3873/ad6692","DOIUrl":"https://doi.org/10.1088/1538-3873/ad6692","url":null,"abstract":"The Mid-Infrared Instrument Medium Resolution Spectrometer (the MRS) on JWST has potentially important advantages for transit and eclipse spectroscopy of exoplanets, including lack of saturation for bright host stars, wavelength span to longward of 20 µm, and JWST’s highest spectral resolving power. We here test the performance of the MRS for time series spectroscopy by observing the secondary eclipse of the bright stellar eclipsing binary R Canis Majoris. Our observations push the MRS into saturation at the shortest wavelength, more than for any currently known exoplanet system. We find strong charge migration between pixels that we mitigate using a custom data analysis pipeline. Our data analysis recovers much of the spatial charge migration by combining detector pixels at the group level, via weighting by the point-spread function. We achieve nearly photon-limited performance in time series data at wavelengths longward of 5.2 µm. In 2017, Snellen et al. suggested that the MRS could be used to detect carbon dioxide absorption from the atmosphere of the temperate planet orbiting Proxima Centauri. We infer that the relative spectral response of the MRS versus wavelength is sufficiently stable to make that detection feasible. As regards the secondary eclipse of this Algol-type binary, we measure the eclipse depth by summing our spectra over the wavelengths in four channels, and also measuring the eclipse depth as observed by TESS. Those eclipse depths require a temperature for the secondary star that is significantly hotter than previous observations in the optical to near-IR, probably due to irradiation by the primary star. At full spectral resolution of the MRS, we find atomic hydrogen recombination emission lines in the secondary star, from principal quantum levels n = 7, 8, 10, and 14.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141936509","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}
引用次数: 0
An Infrared Census of R Coronae Borealis Stars II—Spectroscopic Classifications and Implications for the Rate of Low-mass White Dwarf Mergers 北冕座 R 星的红外普查 II--光谱分类及其对低质量白矮星合并率的影响
IF 3.5 3区 物理与天体物理
Publications of the Astronomical Society of the Pacific Pub Date : 2024-08-04 DOI: 10.1088/1538-3873/ad6210
Viraj R. Karambelkar, Mansi M. Kasliwal, Patrick Tisserand, Shreya Anand, Michael C. B. Ashley, Lars Bildsten, Geoffrey C. Clayton, Courtney C. Crawford, Kishalay De, Nicholas Earley, Matthew J. Hankins, Xander Hall, Astrid Lamberts, Ryan M. Lau, Dan McKenna, Anna Moore, Eran O. Ofek, Roger M. Smith, Roberto Soria, Jamie Soon and Tony Travouillon
{"title":"An Infrared Census of R Coronae Borealis Stars II—Spectroscopic Classifications and Implications for the Rate of Low-mass White Dwarf Mergers","authors":"Viraj R. Karambelkar, Mansi M. Kasliwal, Patrick Tisserand, Shreya Anand, Michael C. B. Ashley, Lars Bildsten, Geoffrey C. Clayton, Courtney C. Crawford, Kishalay De, Nicholas Earley, Matthew J. Hankins, Xander Hall, Astrid Lamberts, Ryan M. Lau, Dan McKenna, Anna Moore, Eran O. Ofek, Roger M. Smith, Roberto Soria, Jamie Soon and Tony Travouillon","doi":"10.1088/1538-3873/ad6210","DOIUrl":"https://doi.org/10.1088/1538-3873/ad6210","url":null,"abstract":"We present results from a systematic infrared (IR) census of R Coronae Borealis (RCB) stars in the Milky Way, using data from the Palomar Gattini IR (PGIR) survey. RCB stars are dusty, erratic variable stars presumably formed from the merger of a He-core and a CO-core white dwarf (WD). PGIR is a 30 cm J-band telescope with a 25 deg2 camera that surveys 18,000 deg2 of the northern sky (δ > −28°) at a cadence of 2 days. Using PGIR J-band lightcurves for ∼60 million stars together with mid-IR colors from WISE, we selected a sample of 530 candidate RCB stars. We obtained near-IR spectra for these candidates and identified 53 RCB stars in our sample. Accounting for our selection criteria, we find that there are a total of RCB stars in the Milky Way. Assuming typical RCB lifetimes, this corresponds to an RCB formation rate of 0.8–5 × 10−3 yr−1, consistent with observational and theoretical estimates of the He-CO WD merger rate. We searched for quasi-periodic pulsations in the PGIR lightcurves of RCB stars and present pulsation periods for 16 RCB stars. We also examined high-cadenced TESS lightcurves for RCB and the chemically similar, but dustless hydrogen-deficient carbon (dLHdC) stars. We find that dLHdC stars show variations on timescales shorter than RCB stars, suggesting that they may have lower masses than RCB stars. Finally, we identified 3 new spectroscopically confirmed and 12 candidate Galactic DY Per type stars—believed to be colder cousins of RCB star—doubling the sample of Galactic DY Per type stars.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141936508","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}
引用次数: 0
Exocomet Models in Transit: Light Curve Morphology in the Optical—Near Infrared Wavelength Range 飞行中的Exocomet模型:光学-近红外波长范围内的光曲线形态学
IF 3.5 3区 物理与天体物理
Publications of the Astronomical Society of the Pacific Pub Date : 2024-08-01 DOI: 10.1088/1538-3873/ad4fe3
Szilárd Kálmán, Gyula M. Szabó and Csaba Kiss
{"title":"Exocomet Models in Transit: Light Curve Morphology in the Optical—Near Infrared Wavelength Range","authors":"Szilárd Kálmán, Gyula M. Szabó and Csaba Kiss","doi":"10.1088/1538-3873/ad4fe3","DOIUrl":"https://doi.org/10.1088/1538-3873/ad4fe3","url":null,"abstract":"Following the widespread practice of exoplanetary transit simulations, various presumed components of an extrasolar system can be examined in numerically simulated transits, including exomoons, rings around planets, and the deformation of exoplanets. Template signals can then be used to efficiently search for light curve features that mark specific phenomena in the data, and they also provide a basis for feasibility studies of instruments and search programs. In this paper, we present a method for exocomet transit light curve calculations using arbitrary dust distributions in transit. The calculations, spanning four distinct materials (carbon, graphite, pyroxene, and olivine), and multiple dust grain sizes (100–300 nm, 300–1000 nm, and 1000–3000 nm) encompass light curves in VRJHKL bands. We also investigated the behavior of scattering colors. We show that multicolor photometric observations are highly effective tools in the detection and characterization of exocomet transits. They provide information on the dust distribution of the comet (encoded in the light curve shape), while the color information itself can reveal the particle size change and material composition of the transiting material, in relation to the surrounding environment. We also show that the typical cometary tail can result in the wavelength dependence of the transit timing. We demonstrate that multi-wavelength observations can yield compelling evidence for the presence of exocomets in real observations.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141936396","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}
引用次数: 0
A Diamond Ring in X-Ray: Investigating the Diffuse Emission of Supernova Remnant G28.8+1.5 X射线中的钻石环:研究超新星剩余物G28.8+1.5的漫射辐射
IF 3.5 3区 物理与天体物理
Publications of the Astronomical Society of the Pacific Pub Date : 2024-07-24 DOI: 10.1088/1538-3873/ad6105
Kaiyue Zhang
{"title":"A Diamond Ring in X-Ray: Investigating the Diffuse Emission of Supernova Remnant G28.8+1.5","authors":"Kaiyue Zhang","doi":"10.1088/1538-3873/ad6105","DOIUrl":"https://doi.org/10.1088/1538-3873/ad6105","url":null,"abstract":"Supernova remnants are products of supernova explosions, which are usually observed in the X-ray band. However, the diffuse emission from the galactic supernova remnant G28.8+1.5 has been overlooked following initial searches for pulsars and pulsar wind nebulae. This paper presents background-subtracted imaging and spatial-resolved spectral analyses using archival XMM-Newton data to reveal unprecedented details of the diffuse emission, providing updated estimates of distance and age. For the first time, an iron overabundance is revealed and the progenitor is suggested to be 9–15 M⊙. These findings refine our understanding of G28.8+1.5 and contribute to a broader comprehension of the Galactic supernova remnant family.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141770721","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}
引用次数: 0
AstroSat/UVIT Study of the Diffuse Ultraviolet Radiation in the Dwarf Galaxy Holmberg II AstroSat/UVIT 对矮星系霍尔姆伯格 II 漫紫外线辐射的研究
IF 3.5 3区 物理与天体物理
Publications of the Astronomical Society of the Pacific Pub Date : 2024-07-23 DOI: 10.1088/1538-3873/ad5d14
Olag Pratim Bordoloi, B. Ananthamoorthy, P. Shalima, Margarita Safonova, Debbijoy Bhattacharya, Yuri A. Shchekinov and Rupjyoti Gogoi
{"title":"AstroSat/UVIT Study of the Diffuse Ultraviolet Radiation in the Dwarf Galaxy Holmberg II","authors":"Olag Pratim Bordoloi, B. Ananthamoorthy, P. Shalima, Margarita Safonova, Debbijoy Bhattacharya, Yuri A. Shchekinov and Rupjyoti Gogoi","doi":"10.1088/1538-3873/ad5d14","DOIUrl":"https://doi.org/10.1088/1538-3873/ad5d14","url":null,"abstract":"We present measurements of diffuse ultraviolet (UV) emission in the dwarf irregular galaxy Holmberg II obtained with the Ultra Violet Imaging Telescope (UVIT) instrument onboard AstroSat, India’s first multiwavelength space mission. With a spatial resolution of 1.″2–1.″6, these are the highest resolution UV observations of the galaxy to date. We find that diffuse emission accounts for ∼70.6% of the total far-ultraviolet (FUV) and for ~58.1% of the total near-ultraviolet (NUV) emission. In the FUV, this is reasonably close to the fraction reported for the SMC bar. We perform a UV–IR correlation study of the diffuse emission in this galaxy using infrared (IR) observations from the Spitzer Space Telescope and Herschel Space Observatory for selected locations, free of detectable bright point sources. The strongest positive correlation between FUV and IR is observed at 70 μm for high H i density (N(H i) > 1 × 1021 cm−2) locations, indicating that warm dust grains dominate the IR emission, in agreement with earlier studies, while NUV is better correlated with 160 μm emission associated with cold dust grains. Low H i density regions (N(H i) < 1 × 1021 cm−2), or cavities, do not show any significant UV–IR correlation except at 160 μm, implying either the presence of colder dust grains in cavities being irradiated by the general radiation field, or insufficient amount of dust. The dust scattering contribution in high H i density regions, estimated using a single scattering model with foreground dust clouds with LMC reddening, gives best-fit albedo and asymmetry factor values of α = 0.2 and g = 0.5, respectively, in reasonable agreement with the theoretical predictions for LMC dust. Our model-derived scattering optical depths in the FUV range from 0.02 to 0.12, implying the medium is optically thin. Therefore, in high H i density regions, dust scattering can be one of the sources of the observed diffuse UV emission, apart from possible contributions from H2 fluorescence. However, the diffuse UV component in H i cavities can only be explained via other mechanisms, such as two-photon emission.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141770720","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}
引用次数: 0
A Digital Backend with Pulse Detection for Radar Astronomy 雷达天文学脉冲检测数字后端
IF 3.5 3区 物理与天体物理
Publications of the Astronomical Society of the Pacific Pub Date : 2024-07-21 DOI: 10.1088/1538-3873/ad5fbc
Gaojing Li, Qiao Meng, Jingsong Ping, Jing Sun, Song Yang, Chenye Zhou, Shaocong Guo and Jie Wu
{"title":"A Digital Backend with Pulse Detection for Radar Astronomy","authors":"Gaojing Li, Qiao Meng, Jingsong Ping, Jing Sun, Song Yang, Chenye Zhou, Shaocong Guo and Jie Wu","doi":"10.1088/1538-3873/ad5fbc","DOIUrl":"https://doi.org/10.1088/1538-3873/ad5fbc","url":null,"abstract":"In radar astronomy, the digital backend and data recording system process and store echo signals in real-time, facilitating the monitoring of near-earth objects such as space debris, satellites, and asteroids. In this paper, a radar astronomy digital backend (RADB), designed for radar astronomy observation and data recording, is proposed. With a sampling rate of 1.12 GSps, the RADB accommodates various analog intermediate frequency (IF) front-ends. In addition to continuously recording echo signals, the RADB has three pulse storage modes and employs an architecture that combines a two-stage decimation (TSD) unit and a decimated pulse detection (DPD) unit. The TSD unit reduces the sampling frequency based on the bandwidth of the signal, after shifting the IF signal to the baseband. Compared to a single-stage decimation, the proposed TSD structure effectively reduces FIR resource consumption without compromising performance. Meanwhile, the DPD unit identifies pulse echo signals and selectively enables the backend to store data only when pulses are detected. This process further reduces the burden on data transmission and storage. Furthermore, the matched filtering pulse detection method in the DPD unit enhances triggering performance, particularly under weak signal conditions. Preliminary performance evaluations in a laboratory demonstrate that the TSD unit reduces data volume by 56 times, while the DPD unit achieves a further reduction of 20 times. Concurrently, a Moon reflection experiment is also conducted at the Yunnan Kunming Electromagnetic Environment Observation and Research Station by using a 29 m antenna. Analysis and processing of stored data validate the effectiveness of the proposed design.","PeriodicalId":20820,"journal":{"name":"Publications of the Astronomical Society of the Pacific","volume":null,"pages":null},"PeriodicalIF":3.5,"publicationDate":"2024-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141737745","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}
引用次数: 0
0
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
相关产品
×
本文献相关产品
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信