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5531. 500um risers with HerMES & SPIRE drop-outs with S2CLS
ID:
ivo://CDS.VizieR/J/ApJS/249/1
Title:
500um risers with HerMES & SPIRE drop-outs with S2CLS
Short Name:
J/ApJS/249/1
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of our systematic search for the reddest far-infrared (FIR) and submillimeter (sub-mm) galaxies using the data from the Herschel Multi-tiered Extragalactic Survey (HerMES) and the SCUBA2 Cosmological Legacy Survey (S2CLS). The red FIR galaxies are "500{mu}m risers," whose spectral energy distributions increase with wavelength across the three FIR passbands of the Spectral and Photometric Imaging REceiver (SPIRE) of Herschel. Within 106.5deg^2^ of the HerMES fields, we have selected 629 500{mu}m risers. The red sub-mm galaxies are "SPIRE drop-outs," which are prominent detections in the S2CLS 850{mu}m data but are extremely weak or invisible in the SPIRE bands. Within the 2.98deg^2^ common area of HerMES and S2CLS, we have selected 95 such objects. These very red sources could be dusty starbursts at high redshifts (z>~4-6) because the peak of their cold-dust emission heated by star formation is shifted to the reddest FIR/sub-mm bands. The surface density of 500{mu}m risers is ~8.2deg^-2^ at the >=20mJy level in 500{mu}m, while that of SPIRE drop-outs is ~19.3deg^-2^ at the >=5mJy level in 850{mu}m. Both types of objects could span a wide range of redshifts, however. Using deep radio data in these fields to further select the ones likely at the highest redshifts, we find that the surface density of z>6 candidates is 5.5deg^-2^ among 500{mu}m risers and is 0.8-13.6deg^-2^ among SPIRE drop-outs. If this is correct, the dust-embedded star formation processes in such objects could contribute comparably as Lyman-break galaxies to the global SFR density at z>6.
5532. 3.6um surface brightness from S4G
ID:
ivo://CDS.VizieR/J/ApJ/772/135
Title:
3.6um surface brightness from S4G
Short Name:
J/ApJ/772/135
Date:
21 Oct 2021
Publisher:
CDS
Description:
We study the m=1 distortions (lopsidedness) in the stellar components of 167 nearby galaxies that span a wide range of morphologies and luminosities. We confirm the previous findings of (1) a high incidence of lopsidedness in the stellar distributions, (2) increasing lopsidedness as a function of radius out to at least 3.5 exponential scale lengths, and (3) greater lopsidedness, over these radii, for galaxies of later type and lower surface brightness. Additionally, the magnitude of the lopsidedness (1) correlates with the character of the spiral arms (stronger arm patterns occur in galaxies with less lopsidedness), (2) is not correlated with the presence or absence of a bar, or the strength of the bar when one is present, (3) is inversely correlated to the stellar mass fraction, f_*_, within one radial scale length, and (4) correlates directly with f_*_ measured within the radial range over which we measure lopsidedness. We interpret these findings to mean that lopsidedness is a generic feature of galaxies and does not, generally, depend on a rare event, such as a direct accretion of a satellite galaxy onto the disk of the parent galaxy. While lopsidedness may be caused by several phenomena, moderate lopsidedness (<A_1_>_i_+<A_1_>_o_)/2<0.3) is likely to reflect halo asymmetries to which the disk responds or a gravitationally self-generated mode. We hypothesize that the magnitude of the stellar response depends both on how centrally concentrated the stars are with respect to the dark matter and whether there are enough stars in the region of the lopsidedness that self-gravity is dynamically important.
5533. UNAM-KIAS catalog of isolated galaxies
ID:
ivo://CDS.VizieR/J/AJ/139/2525
Title:
UNAM-KIAS catalog of isolated galaxies
Short Name:
J/AJ/139/2525
Date:
21 Oct 2021
Publisher:
CDS
Description:
A new catalog of isolated galaxies from the Sloan Digital Sky Survey Data Release 5 (SDSS DR5) is presented. A total of 1520 isolated galaxies were found in 1.4sr of sky. The selection criteria in this UNAM-KIAS catalog are a variation on the criteria developed by Karachentseva, including full redshift information. Through an image processing pipeline that takes advantage of the high-resolution (~0.4"/pix) and high dynamic range of the SDSS images, a uniform g-band morphological classification for all these galaxies is presented.
5534. "Under-massive" black hole candidates
ID:
ivo://CDS.VizieR/J/ApJ/798/54
Title:
"Under-massive" black hole candidates
Short Name:
J/ApJ/798/54
Date:
21 Oct 2021
Publisher:
CDS
Description:
Several recent papers have reported on the occurrence of active galactic nuclei (AGNs) containing undermassive black holes relative to a linear scaling relation between black hole mass (M_bh_) and host spheroid stellar mass (M_sph,*_). However, dramatic revisions to the M_bh_-M_sph,*_ and M_bh_-L_sph_ relations, based on samples containing predominantly inactive galaxies, have recently identified a new steeper relation at M_bh_<~(2-10)x10^8^M_{sun}_, roughly corresponding to M_sph,*_<~(0.3-1)x10^11^M_{sun}_. We show that this steeper, quadratic-like M_bh_-M_sph,*_ relation defined by the Sersic galaxies, i.e., galaxies without partially depleted cores, roughly tracks the apparent offset of the AGN having 10^5^<~M_bh_/M_{sun}_<~0.5x10^8^. That is, these AGNs are not randomly offset with low black hole masses, but also follow a steeper (nonlinear) relation. As noted by Busch et al. (2014, J/A+A/561/A140), confirmation or rejection of a possible AGN offset from the steeper M_bh_-M _sph,*_ relation defined by the Sersic galaxies will benefit from improved stellar mass-to-light ratios for the spheroids hosting these AGNs. Several implications for formation theories are noted. Furthermore, reasons for possible under- and overmassive black holes, the potential existence of intermediate mass black holes (<10^5^M_{sun}_), and the new steep (black hole)-(nuclear star cluster) relation, M_bh_{propto}M_nc_^2.7+/-0.7^, are also discussed.
5535. Unidentified {gamma}-ray sources. III. Radio
ID:
ivo://CDS.VizieR/J/ApJS/207/4
Title:
Unidentified {gamma}-ray sources. III. Radio
Short Name:
J/ApJS/207/4
Date:
21 Oct 2021
Publisher:
CDS
Description:
About one-third of the {gamma}-ray sources listed in the second Fermi Large Area Telescope catalog (2FGL) have no firmly established counterpart at lower energies and so are classified as unidentified {gamma}-ray sources (UGSs). Here, we propose a new approach to find candidate counterparts for the UGSs based on the 325 MHz radio survey performed with the Westerbork Synthesis Radio Telescope in the northern hemisphere. First, we investigate the low-frequency radio properties of blazars, the largest known population of {gamma}-ray sources; then we search for sources with similar radio properties combining the information derived from the Westerbork Northern Sky Survey (WENSS, Rengelink et al. 1997, Cat. J/A+AS/124/259; superseded by Cat. VIII/62) with those of the NRAO Very Large Array Sky Survey (NVSS, Condon et al. 1998, Cat. VIII/65). We present a list of candidate counterparts for 32 UGSs with at least one counterpart in the WENSS. We also performed an extensive research in the literature to look for infrared and optical counterparts of the {gamma}-ray blazar candidates selected using the low-frequency radio observations to confirm their nature. On the basis of our multifrequency research, we identify 23 new {gamma}-ray blazar candidates out of the 32 UGSs investigated. Comparison with previous results on the UGSs is also presented. Finally, we speculate on the advantages of using low-frequency radio observations to associate UGSs and to search for {gamma}-ray pulsar candidates.
5536. Unidentified gamma-ray sources. IV. X-ray
ID:
ivo://CDS.VizieR/J/ApJS/209/9
Title:
Unidentified gamma-ray sources. IV. X-ray
Short Name:
J/ApJS/209/9
Date:
21 Oct 2021
Publisher:
CDS
Description:
A significant fraction (~30%) of the high-energy {gamma}-ray sources listed in the second Fermi Large Area Telescope (LAT) catalog are still of unknown origin, having not yet been associated with counterparts at lower energies. To investigate the nature of these enigmatic sources, we present an extensive search of X-ray sources lying in the positional uncertainty region of a selected sample of these unidentified gamma-ray sources (UGSs) that makes use of all available observations performed by the Swift X-ray Telescope before 2013 March 31, available for 205 UGSs. To detect the fainter sources, we merged all the observations covering the Fermi LAT positional uncertainty region at a 95% level of confidence of each UGS. This yields a catalog of 357 X-ray sources, finding candidate X-ray counterparts for ~70% of the selected sample. In particular, 25% of the UGSs feature a single X-ray source within their positional uncertainty region, while 45% have multiple X-ray sources. For each X-ray source, we also looked in the corresponding Swift UVOT merged images for optical and ultraviolet counterparts, also performing source photometry. We found ultraviolet-optical correspondences for ~70% of the X-ray sources. We searched several major radio, infrared, optical, and ultraviolet surveys for possible counterparts within the positional error of the sources in the X-ray catalog to obtain additional information on their nature. Applying the kernel density estimation technique to infrared colors of Wide-Field Infrared Survey Explorer counterparts of our X-ray sources we select six {gamma}-ray blazar candidates. In addition, comparing our results with previous analyses, we select 11 additional {gamma}-ray blazar candidates.
5537. Unidentified X-ray sources in XMM Slew Survey
ID:
ivo://CDS.VizieR/J/MNRAS/412/1853
Title:
Unidentified X-ray sources in XMM Slew Survey
Short Name:
J/MNRAS/412/1853
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present deep Swift follow-up observations of a sample of 94 unidentified X-ray sources from the XMM-Newton Slew Survey. The X-ray Telescope (XRT) on-board Swift detected 29 per cent of the sample sources; the flux limits for undetected sources suggest the bulk of the Slew Survey sources are drawn from one or more transient populations. We report revised X-ray positions for the XRT-detected sources, with typical uncertainties of 2.9 arcsec, reducing the number of catalogued optical matches to just a single source in most cases. We characterize the sources detected by Swift through their X-ray spectra and variability and via Ultraviolet-Optical Telescope photometry and using catalogued near-infrared, optical and radio observations of potential counterparts. Six sources can be associated with known objects and eight sources may be associated with unidentified ROSAT sources within the 3{sigma} error radii of our revised X-ray positions.
5538. 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.
5539. 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.
5540. 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.