- ID:
- ivo://CDS.VizieR/J/ApJ/749/18
- Title:
- Swift/UVOT observations of 12 nearby SN-Ia
- Short Name:
- J/ApJ/749/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We compare early ultraviolet (UV) observations of Type Ia supernovae (SNe Ia) with theoretical predictions for the brightness of the shock associated with the collision between SN ejecta and a companion star. Our simple method is independent of the intrinsic flux from the SN and treats the flux observed with the Swift/Ultra-Violet Optical Telescope as conservative upper limits on the shock brightness. Comparing this limit with the predicted flux for various shock models, we constrain the geometry of the SN progenitor-companion system. We find the model of a 1 M_{sun}_ red supergiant companion in Roche-lobe overflow to be excluded at a 95% confidence level for most individual SNe for all but the most unfavorable viewing angles. For the sample of 12 SNe taken together, the upper limits on the viewing angle are inconsistent with the expected distribution of viewing angles for red gaint stars as the majority of companions with high confidence. The separation distance constraints do allow main-sequence companions. A better understanding of the UV flux arising from the SN itself as well as continued UV observations of young SNe Ia will further constrain the possible progenitors of SNe Ia.
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- ID:
- ivo://CDS.VizieR/II/339
- Title:
- Swift/UVOT Serendipitous Source Catalog
- Short Name:
- II/339
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The first version of the Swift UVOT serendipitous source catalogue (UVOTSSC) provides positions and magnitudes, as well as errors and upper limits of confirmed sources for observations taken from start of operations in 2005 until October 1st of 2010. The first version of the Swift UVOT Serendipitous Source Catalogue (UVOTSSC) has been produced by processing the image data obtained from the Swift Ultraviolet and Optical Telescope (UVOT) from the beginning of the mission (2005) until 1st of October of 2010. The data processing was performed at the Mullard Space Science Laboratory (MSSL, University College London, U.K.) using Swift FTOOLS from NASA's High Energy Astrophysics Software (HEASoft-6.11), with some customising of the UVOT packages in order to get more complete source detection and properly apply quality flags to those sources that were detected within the UVOT image artefacts. The total number of observations with 17'x17' images used for version 1 of the catalogue is 23,059, giving 6,200,016 sources in total, of which 2,027,265 have multiple entries in the source table because they have been detected in more than one observation. Some sources were only observed in one filter. The total number of entries in the source table is 13,860,568. The S/N ratio for all sources exceeds 5 for at least one UVOT filter, the rest of the filters having a S/N greater than 3.
- ID:
- ivo://CDS.VizieR/J/AJ/158/35
- Title:
- Swift UVOT Stars Survey. III. Galactic open clusters
- Short Name:
- J/AJ/158/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As part of the Swift/Ultraviolet-Optical Telescope Stars Survey, we present near-ultraviolet (NUV; 3000-1700 {AA}) point-source photometry for 103 Galactic open clusters. These data, taken over the span of the mission, provide a unique and unprecedented set of NUV point-source photometry on simple stellar populations. After applying a membership analysis fueled mostly by Gaia DR2 (Cat. I/345) proper motions, we find that 49 of these 103 have clear precise color-magnitude diagrams (CMDs) amenable to investigation. We compare the CMDs to theoretical isochrones and find good agreement between the theoretical isochrones and the CMDs. The exceptions are the fainter parts of the main sequence and the red giant branch in the uvw2-uvw1 CMDs, which is most likely due to either the difficulty of correcting for the red leak in the uvw2 filter or limitations in our understanding of UV opacities for cool stars. For the most part, our derived cluster parameters - age, distance, and reddening - agree with the consensus literature, but we find a few clusters that warrant substantial revision from literature values, notably NGC 2304, NGC 2343, NGC 2360, NGC 2396, NGC 2428, NGC 2509, NGC 2533, NGC 2571, NGC 2818, Collinder 220, and NGC 6939. A number of these are clusters in the third Galactic quadrant, where previous studies may have mistaken the disk sequence for the cluster. However, the Gaia DR2 proper motions clearly favor a different sequence. A number of clusters also show white dwarf and blue straggler sequences. We confirm the presence of extended main-sequence turnoffs in NGC 2360 and NGC 2818 and show hints of them in a number of other clusters that may warrant future spectroscopic study. Most of the clusters in the study have low extinction, and the rest are well fit by a "Milky Way-like" extinction law. However, Collinder 220 hints at a possible "LMC-like" extinction law. We finally provide a comprehensive point-source catalog to the community as a tool for future investigation.
- ID:
- ivo://CDS.VizieR/J/ApJS/208/25
- Title:
- Swift X-ray observations of 1FGL sources
- Short Name:
- J/ApJS/208/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have analyzed all the archival X-ray data of 134 unidentified (unID) gamma-ray sources listed in the first Fermi/LAT (1FGL) catalog and subsequently followed up by the Swift/XRT. We constructed the spectral energy distributions (SEDs) from radio to gamma-rays for each X-ray source detected, and tried to pick up unique objects that display anomalous spectral signatures. In these analyses, we target all the 1FGL unID sources, using updated data from the second Fermi/LAT (2FGL) catalog on the Large Area Telescope (LAT) position and spectra. We found several potentially interesting objects, particularly three sources, 1FGL J0022.2-1850, 1FGL J0038.0+1236, and 1FGL J0157.0-5259, which were then more deeply observed with Suzaku as a part of an AO-7 program in 2012. We successfully detected an X-ray counterpart for each source whose X-ray spectra were well fitted by a single power-law function. The positional coincidence with a bright radio counterpart (currently identified as an active galactic nucleus, AGN) in the 2FGL error circles suggests these sources are definitely the X-ray emission from the same AGN, but their SEDs show a wide variety of behavior. In particular, the SED of 1FGL J0038.0+1236 is not easily explained by conventional emission models of blazars. The source 1FGL J0022.2-1850 may be in a transition state between a low-frequency peaked and a high-frequency peaked BL Lac object, and 1FGL J0157.0-5259 could be a rare kind of extreme blazar.
- ID:
- ivo://CDS.VizieR/J/ApJS/185/433
- Title:
- SWIRE/Chandra survey in Lockman Hole Field
- Short Name:
- J/ApJS/185/433
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report a moderate-depth (70ks), contiguous 0.7deg^2^ Chandra survey in the Lockman Hole Field of the Spitzer/SWIRE Legacy Survey coincident with a completed, ultra-deep VLA survey with deep optical and near-infrared imaging in-hand. The primary motivation is to distinguish starburst galaxies and active galactic nuclei (AGNs), including the significant, highly obscured (logN_H_>23) subset. Chandra has detected 775 X-ray sources to a limiting broadband (0.3-8keV) flux ~4x10^-16^erg/cm^2^/s. We present the X-ray catalog, fluxes, hardness ratios, and multi-wavelength fluxes. The logN versus logS agrees with those of previous surveys covering similar flux ranges. The Chandra and Spitzer flux limits are well matched: 771 (99%) of the X-ray sources have infrared (IR) or optical counterparts, and 333 have MIPS 24um detections. There are four optical-only X-ray sources and four with no visible optical/IR counterpart. The very deep (~2.7uJy rms) VLA data yield 251 (>4{sigma}) radio counterparts, 44% of the X-ray sources in the field. More than 40% of the X-ray sources in the VLA field are radio-loud using the classical definition, RL. The majority of these are red and relatively faint in the optical so that the use of RL to select those AGNs with the strongest radio emission becomes questionable. Using the 24um to radio flux ratio (q_24_) instead results in 13 of the 147 AGNs with sufficient data being classified as radio-loud, in good agreement with the ~10% expected for broad-lined AGNs based on optical surveys. We conclude that q_24_ is a more reliable indicator of radio-loudness. Use of RL should be confined to the optically selected type 1 AGN.
- ID:
- ivo://CDS.VizieR/J/ApJ/685/947
- Title:
- SX Phe stars in Fornax. II.
- Short Name:
- J/ApJ/685/947
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out an intensive survey of the northern region of the Fornax dwarf spheroidal galaxy with the aim of detecting the galaxy's short-period pulsating stars (P<0.25 days). Observations collected over three consecutive nights with the Wide Field Imager of the 2.2m MPI telescope at ESO allowed us to detect 85 high-amplitude (0.20-1.00mag in B light) variable stars with periods in the range from 0.046 to 0.126 days, similar to SX Phoenicis stars in Galactic metal-poor stellar populations. The plots of the observed periods vs. the B and V magnitudes show a dispersion largely exceeding the observational errors. To disentangle the matter, we separated the first-overtone from the fundamental-mode pulsators and tentatively identified a group of subluminous variables, about 0.35mag fainter than the others. Their nature as either metal-poor intermediate-age stars or stars formed by the merging of close binary systems is discussed. The rich sample of the Fornax variables also led us to reconstruct the period-luminosity relation for short-period pulsating stars. An excellent linear fit, M_V_=-1.83(+/-0.08)-3.65(+/-0.07)logP_F_, was obtained using 153 {delta} Scuti and SX Phoenicis stars in a number of different stellar systems.
- ID:
- ivo://CDS.VizieR/J/BaltA/17/293
- Title:
- Symbiotic stars multi-epoch UBV(RI)c photometry
- Short Name:
- J/BaltA/17/293
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a multi-epoch, accurate UBVRcIc photometric catalog of 83 symbiotic stars and related objects, measured while calibrating the Henden and Munari (2000, Cat. <J/A+AS/143/343>, 2001, Cat. <J/A+A/372/145>, 2006, Cat. <J/A+A/458/339>) photometric sequences around them. The vast majority of the observations where collected in the time interval between October 19, 1998 to April 21, 2002 with the 1.0-m Ritchey-Chretien telescope of the U.S. Naval Observatory, Flagstaff Station (Arizona). On average, UBVRcIc data are given on 3.6 epochs for each program star. The overall budget error of the data is usually better than 0.01mag.
- ID:
- ivo://CDS.VizieR/J/PASP/122/35
- Title:
- Symbiotic stars on Asiago archive plates
- Short Name:
- J/PASP/122/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Asiago photographic archive has been searched for plates containing the symbiotic stars AS 210, AS 327, AX Per, BF Cyg, CI Cyg, DT Ser, EG And, GH Gem, Hen 2-442, Hen 3-1591, HM Sge, MaC 1-17, NSV 11776, Pe 2-16, Pt 1, PU Vul, RS Oph, T CrB, UV Aur, V1016 Cyg, V1329 Cyg, V352 Aql, V4018 Sgr, Wray 15-1470, and Z And. A total of 1617 good-quality plates imaging the program stars have been found and their brightness has been estimated using the Henden & Munari (2000, Cat. <J/A+AS/143/343>, 2001, Cat. <J/A+A/372/145>, 2006, Cat. <J/A+A/458/339>, 2008, Cat. <J/BaltA/17/293>) UBVRcIc local photometric sequences. The results for the objects with most abundant measurements are discussed.
- ID:
- ivo://CDS.VizieR/J/A+AS/143/343
- Title:
- Symbiotic stars UBV(RI)c photometry
- Short Name:
- J/A+AS/143/343
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present accurate UBV(RI)_C_ photometric sequences around 20 symbiotic stars. The sequences extend over wide brightness and color ranges, and are suited to cover quiescence as well as outburst phases. The sequences are intended to assist both present time photometry as well as measurement of photographic plates from historical archives.
- ID:
- ivo://CDS.VizieR/J/A+A/372/145
- Title:
- Symbiotic stars UBV(RI)c photometry. II.
- Short Name:
- J/A+A/372/145
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present accurate UBV(RI)_C_ photometric sequences for an additional 20 symbiotic stars. As for the 20 targets of Paper I (Henden et al., 2000, Cat. <J/A+AS/143/343>), the sequences extend over wide brightness and color ranges, and are suited to cover both quiescence and outburst phases. The sequences are intended to assist both present time photometry as well as measurement of photographic plates from historical archives.
