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1071. H{alpha} survey of cluster galaxies
ID:
ivo://CDS.VizieR/J/MNRAS/357/1337
Title:
H{alpha} survey of cluster galaxies
Short Name:
J/MNRAS/357/1337
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have extended our H{alpha} objective prism survey of eight low-redshift clusters (viz. Abell 262, 347, 400, 426, 569, 779, 1367 and 1656) to include a complete sample of early-type galaxies within 1.5 Abell radii of the cluster centres. Of the 379 galaxies surveyed, 3 per cent of E, E-S0 galaxies, 6 per cent of S0 galaxies, and 9 per cent of S0/a galaxies were detected in emission. From a comparison of cluster and supercluster field galaxies, we conclude that the frequency of emission-line galaxies (ELGs; W>=20{AA}) is similar for field and cluster early-type galaxies. A similar result has previously been obtained for galaxies of types Sa and later. Together, these results confirm the inference of Biviano et al. (1997A&A...321...84B) that the relative frequency of ELGs in clusters and the field can be entirely accounted for by the different mix of morphological types between the differing environments, and that, for galaxies of a given morphological type, the fraction of ELGs is independent of environment. Detected emission is classified as 'compact' or 'diffuse', identified as circumnuclear starburst or active galactic nucleus (AGN) emission and disc emission, respectively. By comparing spectroscopic data for cluster early-type ELGs with data for field galaxies from the Palomar spectroscopic survey of nearby galactic nuclei, we demonstrate that there is modest evidence for an enhancement of compact H II emission relative to AGN emission in the early-type cluster ELGs as compared to the field. For the cluster early-type galaxies, compact H II emission correlates strongly with a disturbed morphology. This suggests that, as for later-type cluster galaxies, this enhanced compact H II emission can readily be explained as an enhancement of circumnuclear starburst emission due to gravitational tidal interactions, most likely caused by subcluster merging and other on-going processes of cluster virialization.
1072. H{alpha} & UV emission scale heights for edge-on gal.
ID:
ivo://CDS.VizieR/J/ApJ/862/25
Title:
H{alpha} & UV emission scale heights for edge-on gal.
Short Name:
J/ApJ/862/25
Date:
21 Oct 2021
Publisher:
CDS
Description:
We compare vertical profiles of the extraplanar H{alpha} emission to those of the UV emission for 38 nearby edge-on late-type galaxies. It is found that detection of the "diffuse" extraplanar dust (eDust), traced by the vertically extended, scattered UV starlight, always coincides with the presence of the extraplanar H{alpha} emission. A strong correlation between the scale heights of the extraplanar H{alpha} and UV emissions is also found; the scale height at H{alpha} is found to be ~0.74 of the scale height at FUV. Our results may indicate the multiphase nature of the diffuse ionized gas and dust in the galactic halos. The existence of eDust in galaxies where the extraplanar H{alpha} emission is detected suggests that a larger portion of the extraplanar H{alpha} emission than that predicted in previous studies may be caused by H{alpha} photons that originate from HII regions in the galactic plane and are subsequently scattered by the eDust. This possibility raise an advantage in studying the extraplanar diffuse ionized gas. We also find that the scale heights of the extraplanar emissions normalized to the galaxy size correlate well with the star formation rate surface density of the galaxies. The properties of eDust in our galaxies is on a continuation line of that found through previous observations of the extraplanar polycyclic aromatic hydrocarbons emission in more active galaxies known to have galactic winds.
1073. H{alpha}3 V. Coma cluster
ID:
ivo://CDS.VizieR/J/A+A/576/A16
Title:
H{alpha}3 V. Coma cluster
Short Name:
J/A+A/576/A16
Date:
21 Oct 2021
Publisher:
CDS
Description:
Neutral hydrogen represents the major observable baryonic constituent of galaxies that fuels the formation of stars through transformation of molecular hydrogen. The emission of the hydrogen recombination line H{alpha} is the most direct tracer of the process that transforms gas (fuel) into stars. We continue to present H{alpha}3 (acronym for H{alpha}-{alpha}{alpha}), an extensive H{alpha}+[NII] narrow-band imaging campaign of galaxies selected from the HI Arecibo Legacy Fast ALFA Survey (ALFALFA), using the instrumentation available at the San Pedro Martir (SPM) observatory (Mexico). In 48 nights since 2011 we were able to carry out the H{alpha} imaging observations of 724 galaxies in the region of the Coma supercluster 10h<RA<16h ; 24{deg}<Dec<28{deg} and 3900<cz<9000km/s. Of these, 603 are selected from the ALFALFA and constitute a 97% complete sample. They provide for the first time a complete census of the massive star formation properties of local gas-rich galaxies belonging to different environments (cluster vs. filaments), morphological types (spirals vs. dwarf Irr), over a wide range of stellar mass (~10^8^-10^11.5^M_{sun}_) in the Coma supercluster. The present Paper V provides H{alpha} data and derived star formation rates for the observed galaxies.
1074. h and chi Per UBVI,H{alpha} photometry
ID:
ivo://CDS.VizieR/J/AJ/122/248
Title:
h and chi Per UBVI,H{alpha} photometry
Short Name:
J/AJ/122/248
Date:
21 Oct 2021
Publisher:
CDS
Description:
UBVI and H{alpha} photometry is presented for 17319 stars in vicinity of the young double cluster h and {chi} Persei. Our photometry extends over a 37'x1{deg} field centered on the association. We construct reddening contours within the imaged field. We find that the two clusters share a common distance modulus of 11.75+/-0.05 and ages of log[age(yr)]=7.1+/-0.1. From the V-H{alpha} color, a measure of the H{alpha} emission strength, we conduct a survey for emission line objects within the association. We detect a sample of 33 Be stars, eight of which are new detections. We present a scenario of evolutionary enhancement of the Be phenomenon to account for the peak in Be fraction toward the top of the main sequence in the population of h and {chi} Persei and similar young clusters. UBVI and H{alpha} photometry was performed on five nights between 1999 August 17 and 25 at the San Diego State University Mount Laguna Observatory with the 1m telescope and a Loral 2048x2048 CCD.
1075. HAPLESS galaxies sample
ID:
ivo://CDS.VizieR/J/MNRAS/452/397
Title:
HAPLESS galaxies sample
Short Name:
J/MNRAS/452/397
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the properties of the first 250 {mu}m blind sample of nearby galaxies (15<D<46Mpc) containing 42 objects from the Herschel Astrophysical Terahertz Large Area Survey. Herschel's sensitivity probes the faint end of the dust luminosity function for the first time, spanning a range of stellar mass (7.4<M*<11.3log10M_{sun}_), star formation activity (-11.8<SSFR<-8.9log10yr^-1^), gas fraction (3-96 per cent), and colour (0.6<FUV-K_S_<7.0mag). The median cold dust temperature is 14.6K, colder than in the Herschel Reference Survey (18.5K) and Planck Early Release Compact Source Catalogue (17.7K). The mean dust-to-stellar mass ratio in our sample is higher than these surveys by factors of 3.7 and 1.8, with a dust mass volume density of (3.7+/-0.7)x10^5^M_{sun}_/Mpc^3^. Counter-intuitively, we find that the more dust rich a galaxy, the lower its UV attenuation. Over half of our dust-selected sample are very blue in FUV-K_S_ colour, with irregular and/or highly flocculent morphology; these galaxies account for only 6 per cent of the sample's stellar mass but contain over 35 per cent of the dust mass. They are the most actively star-forming galaxies in the sample, with the highest gas fractions and lowest UV attenuation. They also appear to be in an early stage of converting their gas into stars, providing valuable insights into the chemical evolution of young galaxies.
1076. HAQ survey: red QSO candidates follow-up
ID:
ivo://CDS.VizieR/J/ApJS/217/5
Title:
HAQ survey: red QSO candidates follow-up
Short Name:
J/ApJS/217/5
Date:
21 Oct 2021
Publisher:
CDS
Description:
Quasi-stellar objects (QSOs) whose spectral energy distributions (SEDs) are reddened by dust either in their host galaxies or in intervening absorber galaxies are to a large degree missed by optical color selection criteria like the ones used by the Sloan Digital Sky Survey (SDSS). To overcome this bias against red QSOs, we employ a combined optical and near-infrared (near-IR) color selection. In this paper, we present a spectroscopic follow-up campaign of a sample of red candidate QSOs which were selected from the SDSS and the UKIRT Infrared Deep Sky Survey (UKIDSS). The spectroscopic data and SDSS/UKIDSS photometry are supplemented by mid-infrared photometry from the Wide-field Infrared Survey Explorer. In our sample of 159 candidates, 154 (97%) are confirmed to be QSOs. We use a statistical algorithm to identify sightlines with plausible intervening absorption systems and identify nine such cases assuming dust in the absorber similar to Large Magellanic Cloud sightlines. We find absorption systems toward 30 QSOs, 2 of which are consistent with the best-fit absorber redshift from the statistical modeling. Furthermore, we observe a broad range in SED properties of the QSOs as probed by the rest-frame 2{mu}m flux. We find QSOs with a strong excess as well as QSOs with a large deficit at rest-frame 2{mu}m relative to a QSO template. Potential solutions to these discrepancies are discussed. Overall, our study demonstrates the high efficiency of the optical/near-IR selection of red QSOs.
1077. HARPS and X-shooter spectra of Southern M dwarfs
ID:
ivo://CDS.VizieR/J/ApJ/878/134
Title:
HARPS and X-shooter spectra of Southern M dwarfs
Short Name:
J/ApJ/878/134
Date:
25 Oct 2021 00:49:19
Publisher:
CDS
Description:
We present the homogeneous analysis of a sample of Southern early-type M dwarfs in the solar neighborhood (d<60pc). We used the MCAL technique to derive the effective temperature Teff, metallicity [Fe/H], and activity index i_a_(H_alpha_) of 420 M stars using HARPS spectra. The effective temperature Teff, surface gravity logg, metallicity [Fe/H], and projected rotational velocity V_rot_sini of 153 M0-M6 dwarfs were determined by fitting the observed intermediate-resolution spectra from the VIS arm of VLT/X-shooter with a grid of BT-Settl stellar atmosphere models. We estimated the typical uncertainties of the fit with X-shooter spectra by varying region-to-region results by {sigma}T_eff_~50K, {sigma}logg~0.2, and {sigma}[Fe/H]~0.2dex. Photometric verification of Teff for the 295 stars from the HARPS sample and the 61 stars from the X-shooter sample is also provided. We compared our results from different methods to estimate absolute uncertainty in determining the physical properties of M dwarfs.
1078. H-ATLAS search for strongly lensed galaxies
ID:
ivo://CDS.VizieR/J/ApJ/749/65
Title:
H-ATLAS search for strongly lensed galaxies
Short Name:
J/ApJ/749/65
Date:
21 Oct 2021
Publisher:
CDS
Description:
While the selection of strongly lensed galaxies (SLGs) with 500{mu}m flux density S_500_>100mJy has proven to be rather straightforward, for many applications it is important to analyze samples larger than the ones obtained when confining ourselves to such a bright limit. Moreover, only by probing to fainter flux densities is it possible to exploit strong lensing to investigate the bulk of the high-z star-forming galaxy population. We describe HALOS (the Herschel-ATLAS Lensed Objects Selection), a method for efficiently selecting fainter candidate SLGs, reaching a surface density of =~1.5-2/deg^2^, i.e., a factor of about 4-6 higher than that at the 100mJy flux limit. HALOS will allow the selection of up to ~1000 candidate SLGs (with amplifications {mu}>~2) over the full H-ATLAS survey area. Applying HALOS to the H-ATLAS Science Demonstration Phase field (=~14.4deg^2^) we find 31 candidate SLGs, whose candidate lenses are identified in the VIKING near-infrared catalog. Using the available information on candidate sources and candidate lenses we tentatively estimate a =~72% purity of the sample. As expected, the purity decreases with decreasing flux density of the sources and with increasing angular separation between candidate sources and lenses. The redshift distribution of the candidate lensed sources is close to that reported for most previous surveys for lensed galaxies, while that of candidate lenses extends to redshifts substantially higher than found in the other surveys. The counts of candidate SLGs are also in good agreement with model predictions. Even though a key ingredient of the method is the deep near-infrared VIKING photometry, we show that H-ATLAS data alone allow the selection of a similarly deep sample of candidate SLGs with an efficiency close to 50%; a slightly lower surface density (=~ 1.45/deg2) can be reached with a ~70% efficiency.
1079. HATNet Pleiades Rotation Period Catalogue
ID:
ivo://CDS.VizieR/J/MNRAS/408/475
Title:
HATNet Pleiades Rotation Period Catalogue
Short Name:
J/MNRAS/408/475
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using data from the Hungarian-made Automated Telescope Network (HATNet) survey for transiting exoplanets, we measure photometric rotation periods for 368 Pleiades stars with 0.4~<M~<1.3M_{sun}_. We detect periodic variability for 74 per cent of the cluster members in this mass range that are within our field-of-view, and 93 per cent of the members with 0.7~<M~<1.0M_{sun}_. This increases, by a factor of 5, the number of Pleiades members with measured periods. We compare these data to the rich sample of spectroscopically determined projected equatorial rotation velocities (vsini) available in the literature for this cluster. Included in our sample are 14 newly identified probable cluster members which have proper motions, photometry and rotation periods consistent with membership.
1080. HATNET variability survey
ID:
ivo://CDS.VizieR/J/AJ/128/1761
Title:
HATNET variability survey
Short Name:
J/AJ/128/1761
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Hungarian-made Automated Telescope Network (HATnet) is an ongoing project to detect transiting extrasolar planets using small-aperture (11cm diameter) robotic telescopes. In this paper, we present the results from using image subtraction photometry to reduce a crowded stellar field observed with one of the HATnet telescopes (HAT-5). This field was chosen to overlap with the planned Kepler mission. We obtained I-band light curves for 98,000 objects in a 67 square degree field of view centered at J2000 ({alpha},{delta})=(19h44m00.0s, +37{deg}32'00.0"), near the Galactic plane in the constellations Cygnus and Lyra. These observations include 788 exposures of 5' length over 30-days. For the brightest stars (I~8.0) we achieved a precision of 3.5mmag, falling to 0.1mag at the faint end (I~14). From these light curves we identify 1617 variable stars, of which 1439 are newly discovered.