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16381. Unknown active galactic nuclei study
ID:
ivo://CDS.VizieR/J/A+A/647/A195
Title:
Unknown active galactic nuclei study
Short Name:
J/A+A/647/A195
Date:
21 Oct 2021
Publisher:
CDS
Description:
We collect data at all frequencies for the new sources classified as unknown active galactic nuclei (AGNs) in the latest Burst Alert Telescope all-sky hard X-ray catalog. Focusing on the 36 sources with measured redshift, we compute their spectral energy distribution (SED) from radio to {gamma}-rays with the aim to classify these objects. We apply emission models that attempt to reproduce the obtained SEDs, including: (i) a standard thin accretion disk together with an obscuring torus and a X-ray corona; (ii) a two temperature thick advection-dominated flow; (iii) an obscured AGN model, accounting for absorption along the line of sight at kiloelectronvolt energies and in the optical band; and (iv) a phenomenological model to describe the jet emission in blazar-like objects. We integrate the models with the SWIRE template libraries to account for the emission of the host galaxy. For every source we found a good agreement between data and our model. Considering that the sources were selected in the hard X-ray band, which is rather unaffected by absorption, we expected and found a large fraction of absorbed radio-quiet AGNs (31 out of 36) and some additional rare radio-loud sources (5 out of 36), since the jet emission in hard X-rays is important for aligned jets owing to the boost produced by the beaming effect. With our work we can confirm the hypothesis that a number of galaxies, whose optical spectra lack AGN emission features, host an obscured active nucleus. The approach we used proved to be efficient in rapidly identifying objects, which commonly used methods were not able to classify.
16382. Unresolved binaries in TESS with speckle imaging
ID:
ivo://CDS.VizieR/J/AJ/157/211
Title:
Unresolved binaries in TESS with speckle imaging
Short Name:
J/AJ/157/211
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Transiting Exoplanet Survey Satellite (TESS) is conducting a two-year wide-field survey searching for transiting exoplanets around nearby bright stars that will be ideal for follow-up characterization. To facilitate studies of planet compositions and atmospheric properties, accurate and precise planetary radii need to be derived from the transit light curves. Since 40%-50% of exoplanet host stars are in multiple star systems, however, the observed transit depth may be diluted by the flux of a companion star, causing the radius of the planet to be underestimated. High angular resolution imaging can detect companion stars that are not resolved in the TESS Input Catalog, or by seeing-limited photometry, to validate exoplanet candidates and derive accurate planetary radii. We examine the population of stellar companions that will be detectable around TESS planet candidate host stars, and those that will remain undetected, by applying the detection limits of speckle imaging to the simulated host star populations of Sullivan et al. (2015, J/ApJ/809/77) and Barclay et al. (2018, J/ApJS/239/2). By detecting companions with contrasts of {Delta}m~<7-9 and separations of ~0.02"-1.2", speckle imaging can detect companion stars as faint as early M stars around A-F stars and stars as faint as mid-M around G-M stars, as well as up to 99% of the expected binary star distribution for systems located within a few hundred parsecs.
16383. Unresolved H{alpha} enhancements in WHAM survey
ID:
ivo://CDS.VizieR/J/AJ/129/927
Title:
Unresolved H{alpha} enhancements in WHAM survey
Short Name:
J/AJ/129/927
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have identified 85 regions of enhanced H{alpha} emission at |b|>10{deg} subtending approximately 1{deg} or less on the Wisconsin H{alpha} Mapper (WHAM) sky survey (Cat. II/249). These high-latitude "WHAM point sources" have H{alpha} fluxes of 10^-11^-10^-9^ergs/cm^2^/s, radial velocities within about 70km/s of the LSR, and line widths that range from less than 20 to about 80km/s (FWHM). Twenty-nine of these enhancements are not identified with either cataloged nebulae or hot stars and appear to have kinematic properties that differ from those observed for planetary nebulae. Another 14 enhancements are near hot evolved low-mass stars that had no previously reported detections of associated nebulosity. The remainder of the enhancements are cataloged planetary nebulae and small, high-latitude HII regions surrounding massive O and early B stars.
16384. UNSW catalog of Variable Stars
ID:
ivo://CDS.VizieR/J/MNRAS/385/1749
Title:
UNSW catalog of Variable Stars
Short Name:
J/MNRAS/385/1749
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a new catalogue of variable stars compiled from the data taken for the University of New South Wales Extrasolar Planet Search. From 2004 October to 2007 May, 25 target fields were each observed for one to four months, resulting in ~87000 high-precision light curves with 16004400 data points. We have extracted a total of 850 variable light curves, 659 of which do not have a counterpart in the General Catalogue of Variable Stars, the New Suspected Variables catalogue or the All Sky Automated Survey southern variable star catalogue. The catalogue is detailed here, and includes 142 Algol-type eclipsing binaries, 23 beta Lyrae-type eclipsing binaries, 218 contact eclipsing binaries, 53 RR Lyrae stars, 26 Cepheid stars, 13 rotationally variable active stars, 153 uncategorized pulsating stars with periods <10d, including delta Scuti stars, and 222 long period variables with variability on time-scales of >10d.
16385. Untangling the Galaxy. II. Structure within 3kpc
ID:
ivo://CDS.VizieR/J/AJ/160/279
Title:
Untangling the Galaxy. II. Structure within 3kpc
Short Name:
J/AJ/160/279
Date:
09 Mar 2022 22:00:00
Publisher:
CDS
Description:
We present the results of the hierarchical clustering analysis of the Gaia DR2 data to search for clusters, comoving groups, and other stellar structures. The current paper builds on the sample from the previous work, extending it in distance from 1 to 3kpc and increasing the number of identified structures up to 8292. To aid in the analysis of the population properties, we developed a neural network called Auriga to robustly estimate the age, extinction, and distance of a stellar group based on the input photometry and parallaxes of the individual members. We apply Auriga to derive the properties of not only the structures found in this paper, but also previously identified open clusters. Through this work, we examine the temporal structure of the spiral arms. Specifically, we find that the Sagittarius Arm has moved by >500pc in the last 100Myr and the Perseus Arm has been experiencing a relative lull in star formation activity over the last 25Myr. We confirm the findings of the previous paper on the transient nature of the spiral arms, with the timescale of transition of a few 100Myr. Finally, we find a peculiar ~1Gyr old stream of stars that appears to be heliocentric. Its origin is unclear.
16386. 14 unusual IR transients with Spitzer (SPRITEs)
ID:
ivo://CDS.VizieR/J/ApJ/839/88
Title:
14 unusual IR transients with Spitzer (SPRITEs)
Short Name:
J/ApJ/839/88
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an ongoing, five-year systematic search for extragalactic infrared transients, dubbed SPIRITS-SPitzer InfraRed Intensive Transients Survey. In the first year, using Spitzer/IRAC, we searched 190 nearby galaxies with cadence baselines of one month and six months. We discovered over 1958 variables and 43 transients. Here, we describe the survey design and highlight 14 unusual infrared transients with no optical counterparts to deep limits, which we refer to as SPRITEs (eSPecially Red Intermediate-luminosity Transient Events). SPRITEs are in the infrared luminosity gap between novae and supernovae, with [4.5] absolute magnitudes between -11 and -14 (Vega-mag) and [3.6]-[4.5] colors between 0.3mag and 1.6mag. The photometric evolution of SPRITEs is diverse, ranging from <0.1mag/yr to >7mag/yr. SPRITEs occur in star-forming galaxies. We present an in-depth study of one of them, SPIRITS 14ajc in Messier 83, which shows shock-excited molecular hydrogen emission. This shock may have been triggered by the dynamic decay of a non-hierarchical system of massive stars that led to either the formation of a binary or a protostellar merger.
16387. unWISE Catalog
ID:
ivo://irsa.ipac/WISE/Catalog/unWISE
Title:
unWISE Catalog
Short Name:
unWISECat
Date:
02 Dec 2020 19:45:36
Publisher:
NASA/IPAC Infrared Science Archive
Description:
The unWISE Catalog contains the positions and fluxes of roughly two billion objects observed by the Wide-field Infrared Survey Explorer (WISE) over the full sky. The unWISE Catalog has two advantages over the existing WISE catalog (AllWISE): first, it is based on significantly deeper imaging, and second, it features improved modeling of crowded regions. The deeper imaging used in the unWISE Catalog comes from the coaddition of all publicly available 3-5 micron WISE imaging, including that from the ongoing NEOWISE-Reactivation mission, thereby increasing the total exposure time by a factor of 5 relative to AllWISE. At these depths, even at high Galactic latitudes many sources are blended with their neighbors; accordingly, the unWISE analysis simultaneously fits thousands of sources to obtain accurate photometry. The unWISE catalog detects sources at 5 sigma roughly 0.7 magnitudes fainter than the AllWISE catalog and more accurately models millions of faint sources in the Galactic plane, enabling a wealth of Galactic and extragalactic science. In particular, relative to AllWISE, unWISE doubles the number of galaxies detected between redshifts 0 and 1 and triples the number between redshifts 1 and 2, cataloging more than half a billion galaxies over the whole sky.
16388. Updated AGILE Catalog of Bright Gamma-Ray Sources and Variability
ID:
ivo://nasa.heasarc/agileupvar
Title:
Updated AGILE Catalog of Bright Gamma-Ray Sources and Variability
Short Name:
AGILEUPVAR
Date:
11 Jul 2025
Publisher:
NASA/GSFC HEASARC
Description:
This table contains some of the results from a variability study of a sample of bright gamma-ray (30 MeV - 50 GeV) sources. This sample is an extension of the first AGILE catalog of gamma-ray sources (1AGL), obtained using the complete set of AGILE observations in pointing mode performed during a 2.3 year period from July 9, 2007 until October 30, 2009. The dataset of AGILE pointed observations covers a long time interval and its gamma-ray data archive is useful for monitoring studies of medium-to-high brightness gamma-ray sources. In the analysis reported here, the authors used data obtained with an improved event filter that covers a wider field of view, on a much larger (about 27.5 months) dataset, integrating data on observation block (OB) time scales, which mostly range from a few days to thirty days. The data processing resulted in a better characterized source list than 1AGL was, and includes 54 sources, 7 of which are new high galactic latitude (|b_II_|&gt;= 5 degrees) sources, 8 are new sources on the galactic plane, and 20 sources are from the previous catalogue with revised positions. Eight 1AGL sources (2 high-latitude and 6 on the galactic plane) were not detected in the final processing either because of low OB exposure and/or due to their position in complex galactic regions. The reference paper reports the results in a catalog of all the detections obtained in each single OB, including the variability results for each of these sources. In particular, the authors found that 12 sources out of 42 or 11 out of 53 are variable, depending on the variability index used, where 42 and 53 are the number of sources for which these indices could be calculated. Seven of the 11 variable sources are blazars, the others are the Crab pulsar+nebula, LS I +61 303, Cyg X-3, and 1AGLR J2021+4030. This HEASARC table contains 54 AGILE-detected sources and the main parameters of their maximum significance (defined by sqrt(TS)) detections: for each source, the name, coordinates, the sqrt(TS) value as a measure of the detection significance, the E &gt; 100 MeV flux, the four variability indices described in Section 5 of the reference paper, the number of detections, the confirmed counterparts and source class, if any, and other possible associations ordered according to the angular distance from the AGL source are given. These data are listed in Table 5a of the reference paper. This HEASARC table does not contain the list of fluxes for these sources as measured in all of the relevant individual OBs (Table 5b in the reference paper). This latter is obtainable from the CDS: &lt;a href="http://cdsarc.u-strasbg.fr/ftp/cats/J_A+A/558/A137/table5b.dat"&gt;http://cdsarc.u-strasbg.fr/ftp/cats/J_A+A/558/A137/table5b.dat&lt;/a&gt;. This table was created by the HEASARC in December 2013 based on &lt;a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/558/A137"&gt;CDS catalog J/A+A/558/A137&lt;/a&gt; file table5a.dat. This is a service provided by NASA HEASARC .
16389. Updated calibration of the CSP-I SNe Ia sample
ID:
ivo://CDS.VizieR/J/ApJ/869/56
Title:
Updated calibration of the CSP-I SNe Ia sample
Short Name:
J/ApJ/869/56
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an analysis of the final data release of the Carnegie Supernova Project I (CSP-I; Krisciunas+ 2017, J/AJ/154/211), focusing on the absolute calibration of the luminosity-decline rate relation for Type Ia supernovae (SNe Ia) using new intrinsic color relations with respect to the color-stretch parameter, s_BV_, enabling improved dust extinction corrections. We investigate to what degree the so-called fast-declining SNe Ia can be used to determine accurate extragalactic distances. We estimate the intrinsic scatter in the luminosity-decline rate relation and find it ranges from +/-0.13mag to +/-0.18mag with no obvious dependence on wavelength. Using the Cepheid variable star data from the SH0ES project (Riess+ 2016, J/ApJ/826/56), the SN Ia distance scale is calibrated and the Hubble constant is estimated using our optical and near-infrared sample, and these results are compared to those determined exclusively from a near-infrared subsample. The systematic effect of the supernova's host galaxy mass is investigated as a function of wavelength and is found to decrease toward redder wavelengths, suggesting this effect may be due to dust properties of the host. Using estimates of the dust extinction derived from optical and near-infrared wavelengths and applying these to the H band, we derive a Hubble constant H0=73.2+/-2.3km/s/Mpc, whereas using a simple B-V color correction applied to the B band yields H0=72.7+/-2.1km/s/Mpc. Photometry of two calibrating SNe Ia from the CSP-II sample, SN 2012ht and SN 2015F, is presented and used to improve the calibration of the SN Ia distance ladder.
16390. Updated catalog of GALEX nearby galaxies
ID:
ivo://CDS.VizieR/J/ApJS/220/6
Title:
Updated catalog of GALEX nearby galaxies
Short Name:
J/ApJS/220/6
Date:
21 Oct 2021
Publisher:
CDS
Description:
The ultraviolet (UV) catalog of nearby galaxies compiled by Gil de Paz et al. (2007, J/ApJS/173/185) presents the integrated photometry and surface brightness profiles for 1034 nearby galaxies observed by GALEX. We provide an updated catalog of 4138 nearby galaxies based on the latest General Release (GR6/GR7) of GALEX. These galaxies are selected from HyperLeda with apparent diameters larger than 1'. From the surface brightness profiles accurately measured using the deep NUV and FUV images, we have calculated the asymptotic magnitudes, aperture (D25) magnitudes, colors, structural parameters (effective radii and concentration indices), luminosities, and effective surface brightness for these galaxies. Archival optical and infrared photometry from HyperLeda, 2MASS, and IRAS are also integrated into the catalog. Our parameter measurements and some analyses are consistent with those of Paz et al. The (FUV-K) color provides a good criterion to distinguish between early- and late-type galaxies, which can be improved further using the concentration indices. The IRX-{beta} relation is reformulated with our UV-selected nearby galaxies.

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