- ID:
- ivo://CDS.VizieR/J/MNRAS/415/1935
- Title:
- I-band photometry of cosmic flows
- Short Name:
- J/MNRAS/415/1935
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Within the "Cosmic Flows" project, I-band photometry of 524 relatively nearby galaxies has been carried out over the course of several years with the University of Hawaii 2.2-m telescope and a camera with a 7.5-arcmin field of view. The primary scientific goal was to provide global magnitudes and inclinations for galaxies for the purpose of measuring distances through the correlation between galaxy luminosities and rotation rates. The 1{sigma} accuracy on a total magnitude is 0.08mag. The observations typically extend to 7-8 exponential disc scalelengths, so the data are useful for studies of the structural properties of galaxies.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/452/910
- Title:
- IC 1613 asymptotic giant branch variables
- Short Name:
- J/MNRAS/452/910
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- JHKs photometry is presented from a 3-yr survey of the central regions of the Local Group dwarf irregular galaxy IC 1613. The morphologies of the colour-magnitude and colour-colour diagrams are discussed with particular reference to the supergiants and M- and C-type asymptotic giant branch (AGB) stars. Mean JHKs magnitudes, amplitudes and periods are given for five O-rich and nine C-rich Mira variables for which bolometric magnitudes are also estimated. A distance of 750kpc ((m-M)0=24.37+/-0.08mag) is derived for IC 1613 by fitting a period-luminosity (PL) relation to the C-rich Miras. This is in agreement with values from the literature. The AGB stars exhibit a range of ages. A comparison with theoretical isochrones suggests that four luminous O-rich Miras are as young as 2x10^8^yr. One of these has a lithium absorption line in its spectrum, demonstrating that it is undergoing hot bottom burning (HBB). This supports the idea that HBB is the cause of the high luminosity of these AGB stars, which puts them above the fundamental PL relation. Further studies of similar stars, selected from their positions in the PL diagram, could provide insight into HBB. A much fainter, presumed O-rich, Mira is similar to those found in Galactic globular clusters. The C Miras are of intermediate age. The O-rich variables are not all recognized as O-rich, or even as AGB stars, on the basis of their J-Ks colour. It is important to appreciate this when using near-infrared surveys to classify AGB stars in more distant galaxies.
- ID:
- ivo://CDS.VizieR/J/AJ/135/823
- Title:
- ICMF of super star clusters
- Short Name:
- J/AJ/135/823
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The initial cluster mass function (ICMF) is a fundamental property of star formation in galaxies. To gauge its universality, we measure and compare the ICMFs in irregular and spiral galaxies. Our sample of irregular galaxies is based on 13 nearby galaxies selected from a volume-limited sample from the fifth data release of the Sloan Digital Sky Survey (SDSS), from which about 320 young (<=20Myr), massive (>~3x10^49M_{sun}_) clusters or associations were selected using an automated source extraction routine. The extinctions, ages, and masses were determined by comparing their u'g'i'z' magnitudes to those generated from starburst models.
- ID:
- ivo://CDS.VizieR/J/A+A/578/A93
- Title:
- IC 342 multi-frequency radio polarization study
- Short Name:
- J/A+A/578/A93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Magnetic fields play an important role in the formation and stabilization of spiral structures in galaxies, but the interaction between interstellar gas and magnetic fields has not yet been understood. In particular, the phenomenon of "magnetic arms" located between material arms is a mystery. The strength and structure of interstellar magnetic fields and their relation to spiral arms in gas and dust are investigated in the nearby and almost face-on spiral galaxy IC 342.
- ID:
- ivo://CDS.VizieR/J/A+A/319/33
- Title:
- Identification of X-ray sources around Seyferts
- Short Name:
- J/A+A/319/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Excess numbers of X-ray sources around bright Seyfert galaxies have been demonstrated with significances of association up to 7.4-sigma (Radecke, 1997A&A...319...18R). The optical identification of these sources is shown here to be predominantly blue stellar objects (BSO's) of which some are already catalogued as quasars. Excluding the two brightest Seyferts, a subset of 24 with apparent magnitudes between 8.04<=B_T_^o,i^<=12.90mag. show a minimum excess of >46 bright X-ray sources. These excess X-ray sources are generally distributed between 10'<r<40' and 12 of the Seyferts show conspicuous pairs of X-ray sources across their active nuclei. Additional pairing and alignment of sources is seen for the remaining Seyferts. Among the paired X-ray sources, 53 have been identified as BSO's. Some double and multiple BSO's have been identified which are candidates for groups and associations of quasars. Some groups are well aligned and some centered on small blue galaxies. Four previously known BL Lac objects fall close enough to the Seyferts in this sample to confirm, at a significance level of 1-2x10^-9^, a previously reported association of BL Lac objects with bright, low redshift galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJS/224/18
- Title:
- Identify giant radio sources from the NVSS
- Short Name:
- J/ApJS/224/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results of the application of pattern-recognition techniques to the problem of identifying giant radio sources (GRSs) from the data in the NVSS catalog are presented, and issues affecting the process are explored. Decision-tree pattern-recognition software was applied to training-set source pairs developed from known NVSS large-angular-size radio galaxies. The full training set consisted of 51195 source pairs, 48 of which were known GRSs for which each lobe was primarily represented by a single catalog component. The source pairs had a maximum separation of 20' and a minimum component area of 1.87arcmin^2^ at the 1.4mJy level. The importance of comparing the resulting probability distributions of the training and application sets for cases of unknown class ratio is demonstrated. The probability of correctly ranking a randomly selected (GRS, non-GRS) pair from the best of the tested classifiers was determined to be 97.8+/-1.5%. The best classifiers were applied to the over 870000 candidate pairs from the entire catalog. Images of higher-ranked sources were visually screened, and a table of over 1600 candidates, including morphological annotation, is presented. These systems include doubles and triples, wide-angle tail and narrow-angle tail, S- or Z-shaped systems, and core-jets and resolved cores. While some resolved-lobe systems are recovered with this technique, generally it is expected that such systems would require a different approach.
1757. IDEOS redshift catalogue
- ID:
- ivo://CDS.VizieR/J/MNRAS/455/1796
- Title:
- IDEOS redshift catalogue
- Short Name:
- J/MNRAS/455/1796
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the first of a series of papers on the Infrared Database of Extragalactic Observables from Spitzer (IDEOS). In this work, we describe the identification of optical counterparts of the infrared sources detected in Spitzer Infrared Spectrograph (IRS) observations and the acquisition and validation of redshifts. The IDEOS sample includes all the spectra from the Cornell Atlas of Spitzer/IRS Sources (CASSIS, Lebouteiller et al., 2011ApJS..196....8L, 2015ApJS..218...21L) of galaxies beyond the Local Group. Optical counterparts were identified from correlation of the extraction coordinates with the NASA Extragalactic Database (NED). To confirm the optical association and validate NED redshifts, we measure redshifts with unprecedented accuracy on the IRS spectra ({sigma}({Delta}z/(1+z))~0.0011) by using an improved version of the maximum combined pseudo-likelihood method (MCPL). We perform a multistage verification of redshifts that considers alternate NED redshifts, the MCPL redshift, and visual inspection of the IRS spectrum. The statistics is as follows: the IDEOS sample contains 3361 galaxies at redshift 0<z<6.42 (mean: 0.48, median: 0.14). We confirm the default NED redshift for 2429 sources and identify 124 with incorrect NED redshifts. We obtain IRS-based redshifts for 568 IDEOS sources without optical spectroscopic redshifts, including 228 with no previous redshift measurements. We provide the entire IDEOS redshift catalogue in machine-readable formats. The catalogue condenses our compilation and verification effort, and includes our final evaluation on the most likely redshift for each source, its origin, and reliability estimates.
- ID:
- ivo://CDS.VizieR/J/A+A/581/A65
- Title:
- IFU observations of NGC 4191
- Short Name:
- J/A+A/581/A65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We here distinguish two counter-rotating stellar components in NGC 4191 and characterize their physical properties such as kinematics, size, morphology, age, metallicity. We obtained integral field spectroscopic observations with VIRUS-W and used a spectroscopic decomposition technique to separate the contribution of two stellar components to the observed galaxy spectrum. We also performed a photometric decomposition, modeling the galaxy with a Sersic bulge and two exponential disks of different scale length, with the aim of associating these structural components with the kinematic components. We then measured the equivalent width of the absorption line indices on the best-fit models that represent the kinematic components and compared our measurements to the predictions of stellar population models that also account for the variable abundance ratio of {alpha} elements.
- ID:
- ivo://CDS.VizieR/J/ApJ/588/218
- Title:
- i*g* photometry of SDSS EDR galaxies
- Short Name:
- J/ApJ/588/218
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we present a new statistic for quantifying galaxy morphology based on measurements of the Gini coefficient of galaxy light distributions. This statistic is easy to measure and is commonly used in econometrics to measure how wealth is distributed in human populations. When applied to galaxy images, the Gini coefficient provides a quantitative measure of the inequality with which a galaxy's light is distributed among its constituent pixels. We measure the Gini coefficient of local galaxies in the Early Data Release of the Sloan Digital Sky Survey and demonstrate that this quantity is closely correlated with measurements of central concentration, but with significant scatter.
- ID:
- ivo://CDS.VizieR/J/A+A/442/165
- Title:
- IJKs photometry of late-type stars in Draco dSph
- Short Name:
- J/A+A/442/165
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With the William Herschel Telescope in La Palma we made IJKs observations of an area of about 40'x30' of the Local Group galaxy Draco. This allows us to describe Draco's late-type stellar population across the whole galaxy at a photometric level 2mag deeper than the 2MASS survey. We detected the red giant branch (RGB) and measured the magnitude of the tip of the RGB in the three bands. From that in the I band we obtain a distance modulus of (m-M)_0=19.49+/-0.06(stat)+/-0.15(sys), in excellent agreement with a measurement from RR Lyrae stars. The peak of the (J-Ks)_0_ histogram at different M_Ks_ suggests that Draco has a mean [Fe/H]=-1.95+/-1.26 while fiducial RGB tracks of Galactic globular clusters indicate a mean [Fe/H]=-1.33+/-0.72 where the error corresponds to the spread around the mean value. There are significant differences between the colour-magnitude diagrams of stars in the inner, medium and outer areas of the galaxy. A metal poor (Z=0.0004) intermediate-age population (about 1.6Gyr old) is clearly present and emerges in particular between 6' and 12' from the centre of the galaxy. A few additional carbon star candidates have been identified from both their location in the colour-magnitude diagram and from an indication of variability. The large scale distribution of late-type stars is smooth but irregular in shape; this points at a variation of inclination with radius.