- ID:
- ivo://CDS.VizieR/J/ApJ/788/123
- Title:
- IRTF J-band spectrum of Mrk 231
- Short Name:
- J/ApJ/788/123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first J-band spectrum of Mrk 231, which reveals a large He I* {lambda}10830 broad absorption line with a profile similar to that of the well-known Na I broad absorption line. Combining this spectrum with optical and UV spectra from the literature, we show that the unusual reddening noted by Veilleux et al. (2013ApJ...764...15V) is explained by a reddening curve like those previously used to explain low values of total-to-selective extinction in Type Ia supernovae. The nuclear starburst may be the origin and location of the dust. Spatially resolved emission in the broad absorption line trough suggests nearly full coverage of the continuum emission region. The broad absorption lines reveal higher velocities in the He I* lines (produced in the quasar-photoionized H II region) compared with the Na I and Ca II lines (produced in the corresponding partially ionized zone). Cloudy simulations show that a density increase is required between the H II and partially ionized zones to produce ionic column densities consistent with the optical and IR absorption line measurements and limits, and that the absorber lies ~100 pc from the central engine. These results suggest that the He I* lines are produced in an ordinary quasar BAL wind that impacts upon, compresses, and accelerates the nuclear starburst's dusty effluent (feedback in action), and the Ca II and Na I lines are produced in this dusty accelerated gas. This unusual circumstance explains the rarity of Na I absorption lines; without the compression along our line of sight, Mrk 231 would appear as an ordinary iron low-ionization, broad absorption line quasar.
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- ID:
- ivo://CDS.VizieR/J/ApJ/826/209
- Title:
- IRX-{beta} relation of HII regions in NGC628
- Short Name:
- J/ApJ/826/209
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- It has been found that the infrared-to-ultraviolet luminosity ratio (IRX) and ultraviolet spectral slope ({beta}) have a tight correlation in starburst galaxies, while in normal galaxies the relation is deviated and has a much larger scatter. Star formation regions are much simpler in both morphology and physical properties than galaxies, so their photometric and spectroscopic properties are more easily and accurately determined. We have used the integral field spectroscopy and multiband photometric images to study the IRX-{beta} relation of HII regions in a nearby galaxy, NGC 628. There are obvious correlations between the D_n_ (4000), stellar population age, star formation rate, especially H{alpha} equivalent width EW(H{alpha}), and deviation distance d_p_ from the starburst IRX-{beta} relation. However, there is little correlation between the Balmer decrement, metallicity, and d_p_. It is much more complicated than expected, so that we cannot introduce a single second parameter to describe the scatter and deviation of the HII region IRX-{beta} relation.
- ID:
- ivo://CDS.VizieR/J/ApJ/850/137
- Title:
- ISLAndS project. III. Variable stars
- Short Name:
- J/ApJ/850/137
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a census of variable stars in six M31 dwarf spheroidal satellites observed with the Hubble Space Telescope. We detect 870 RR Lyrae (RRL) stars in the fields of And I (296), II (251), III (111), XV (117), XVI (8), and XXVIII (87). We also detect a total of 15 Anomalous Cepheids, three eclipsing binaries, and seven field RRL stars compatible with being members of the M31 halo or the Giant Stellar Stream. We derive robust and homogeneous distances to the six galaxies using different methods based on the properties of the RRL stars. Working with the up-to-date set of Period-Wesenheit (I, B-I) relations published by Marconi et al., we obtain distance moduli of {mu}0=[24.49, 24.16, 24.36, 24.42, 23.70, 24.43]mag (respectively), with systematic uncertainties of 0.08mag and statistical uncertainties <0.11mag. We have considered an enlarged sample of 16 M31 satellites with published variability studies, and compared their pulsational observables (e.g., periods and amplitudes) with those of 15 Milky Way satellites for which similar data are available. The properties of the (strictly old) RRL in both satellite systems do not show any significant difference. In particular, we found a strikingly similar correlation between the mean period distribution of the fundamental RRL pulsators (RRab) and the mean metallicities of the galaxies. This indicates that the old RRL progenitors were similar at the early stage in the two environments, suggesting very similar characteristics for the earliest stages of evolution of both satellite systems.
- ID:
- ivo://CDS.VizieR/J/A+A/427/773
- Title:
- ISOCAM 14.3{mu}m Deep Survey in Lockman Hole
- Short Name:
- J/A+A/427/773
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new analysis of the ISOCAM 14.3{mu}m deep survey in a 20x20 square arcmin area in the Lockman Hole. This survey is intermediate between the ultra-deep surveys and the shallow surveys in the ELAIS fields. The data have been analyzed with the method presented by Lari et al. (2001, Cat. <J/MNRAS/325/1173>). We have produced a catalogue of 283 sources detected above the 5-{sigma} threshold, with fluxes in the interval 0.1-8mJy. The catalogue is 90% complete at 1mJy. The positional accuracy, estimated from the cross-correlation of infrared and optical sources, is around 1.5arcsec. The search for the optical counterparts of the sources in the survey is performed on a medium-deep r' band optical image (5{sigma} depth of r'=25), making use of the radio detections when available. The photometry has been checked through simulations and by comparing the data with those presented in a shallower and more extended ISOCAM survey in the Lockman Hole, that we have presented in a companion paper. Only 15% of the 14.3{mu}m sources do not have an optical counterpart down to r'=25mag. We use the 6.7/14.3{mu}m colour as a star/galaxy separator, together with a visual inspection of the optical image and an analysis of the observed Spectral Energy Distribution of the ISOCAM sources. The stars in the sample turn out to be only 6% of the sample. We discuss the 14.3{mu}m counts of extragalactic sources, combining our catalogue with that obtained from the shallower ISOCAM survey. The data in the two surveys are consistent, and our results fully support the claims in previous works for the existence of an evolving population of infrared galaxies, confirming the evident departure from non-evolutionary model predictions.
- ID:
- ivo://CDS.VizieR/J/A+AS/141/257
- Title:
- ISOCAM obs. of very deep IRAS 60um sources
- Short Name:
- J/A+AS/141/257
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of ISO observations with the CAM LW3 filter, centered at {lambda}_eff_=14.3{mu}m, of 94 out of the 98 galaxies comprising the complete 60{mu}m IRAS deep survey (IDS) sample in the north ecliptic polar region. In addition, we observed a source detected by IRAS at 25{mu}m and found to have particularly interesting properties. Altogether, 106 sources were detected with a signal to noise ratio >=3 and 69 with S/N>=5 in the 3.2'x3.2' fields centered on the nominal positions of IRAS sources. Sixty-five >=3{sigma} detections (49 of which at >=5{sigma}) are likely identifications of IRAS sources. Ten additional IRAS sources have possible >=3{sigma} ISOCAM counterparts. In 6 further cases, signals at the 2-3{sigma} level were detected close to the IRAS position. Indications that IRAS sources might actually be multiple (source confusion) were found in 4 IDS fields. On the whole, we confirm the reality of 69 to 90% of IDS sources. Appropriate statistical corrections for the bias affecting faint flux estimates were applied to ISOCAM data. Ten serendipitous sources were detected at >=5{sigma}, with S(14.3{mu}m)>=3.5mJy. The corresponding areal density is consistent with that found in previous surveys. Finding charts for all observed fields are given.
1856. ISO ELAIS 15{mu}m survey
- ID:
- ivo://CDS.VizieR/J/MNRAS/325/1173
- Title:
- ISO ELAIS 15{mu}m survey
- Short Name:
- J/MNRAS/325/1173
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We develop a new data reduction technique for ISOCAM LW data and apply it to the European Large Area ISO Survey (ELAIS) LW3 (15-{mu}m) observations in the southern hemisphere (S1). This method, known as LARI technique and based on the assumption of the existence of two different time-scales in ISOCAM transients (accounting for either fast or slow detector response), is particularly designed for the detection of faint sources. In the ELAIS S1 field we obtain a catalogue of 462 15-{mu}m sources with signal-to-noise ratios >=5 and flux densities in the range 0.45-150mJy (filling the whole flux range between the Deep ISOCAM Surveys and the IRAS Faint Source Survey). The completeness at different flux levels and the photometric accuracy of this catalogue are tested with simulations. Here we present a detailed description of the method and discuss the results obtained by its application to the S1 LW3 data.
- ID:
- ivo://CDS.VizieR/J/A+A/372/364
- Title:
- ISO FIRBACK Source Catalog at 170um
- Short Name:
- J/A+A/372/364
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The FIRBACK (Far Infrared BACKground) survey is one of the deepest imaging surveys carried out at 170{mu}m with ISOPHOT onboard ISO, and is aimed at the study of the structure of the Cosmic Far Infrared Background. This paper provides the analysis of resolved sources. After a validated process of data reduction and calibration, we perform intensive simulations to optimize the source extraction, measure the confusion noise ({sigma}_c_=45mJy), and give the photometric and astrometric accuracies. 196 galaxies with flux S>3{sigma}_c_ are detected in the area of 3.89 square degrees. Counts of sources with flux S>4{sigma}_c_ present a steep slope of 3.3+/-0.6 on a differential ``logN-logS'' plot between 180 and 500mJy. As a consequence, the confusion level is high and will impact dramatically on future IR deep surveys. This strong evolution, compared with a slope of 2.5 from Euclidian geometry, is in line with models implying a strongly evolving Luminous Infrared Galaxy population. The resolved sources account for less than 10% of the Cosmic Infrared Background at 170{mu}m, which is expected to be resolved into sources in the 1 to 10mJy range.
- ID:
- ivo://CDS.VizieR/J/other/Sci/348.418
- Title:
- Isolated compact elliptical galaxies
- Short Name:
- J/other/Sci/348.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Compact elliptical galaxies form a rare class of stellar system (~30 presently known) characterized by high stellar densities and small sizes and often harboring metal-rich stars. They were thought to form through tidal stripping of massive progenitors, until two isolated objects were discovered where massive galaxies performing the stripping could not be identified. By mining astronomical survey data, we have now found 195 compact elliptical galaxies in all types of environment. They all share similar dynamical and stellar population properties. Dynamical analysis for nonisolated galaxies demonstrates the feasibility of their ejection from host clusters and groups by three-body encounters, which is in agreement with numerical simulations. Hence, isolated compact elliptical and isolated quiescent dwarf galaxies are tidally stripped systems that ran away from their hosts.
- ID:
- ivo://CDS.VizieR/J/other/KFNT/22.187
- Title:
- Isolated galaxies ident. with IRAS and NVSS
- Short Name:
- J/other/KFNT/22.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We determine some parameters of the far infrared radiation for a sample of isolated galaxies, namely, luminosity, color indices, dust temperature, and current star formation rate and efficiency.
- ID:
- ivo://CDS.VizieR/J/A+A/578/A110
- Title:
- Isolated galaxies, pairs and triplets
- Short Name:
- J/A+A/578/A110
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The construction of catalogues of galaxies and the posterior study of galaxy properties in relation to their environment, have been hampered by the scarce redshift information. The new 3-dimensional (3D) surveys permit to distinguish small, faint, physically bound satellites from a background projected galaxy population, giving a more comprehensive 3D picture of the surroundings. We aim to provide representative samples of isolated galaxies, isolated pairs, and isolated triplets for testing galaxy evolution and secular processes in low density regions of the local Universe, as well as to characterise their local and large-scale environments. We use spectroscopic data from the tenth data release of the Sloan Digital Sky Survey (SDSS-DR10) to automatically and homogeneously compile catalogues of 3,702 isolated galaxies, 1,240 isolated pairs, and 315 isolated triplets in the local Universe (z<=0.080). To quantify the effects of their local and large-scale environments, we compute the projected density and the tidal strength for the brightest galaxy in each sample. We find evidence of isolated pairs and isolated triplets physically bound at projected separation up to d<=450kpc with radial velocity difference {Delta}v<=160km/s, where the effect of the companion typically accounts for more than 98% of the total tidal strength affecting the central galaxy. For galaxies in the catalogues, we provide their positions, redshifts, and degrees of relation with their physical and large-scale environments. The catalogues are publicly available to the scientific community. For isolated galaxies, isolated pairs, and isolated triplets there is no difference in their degree of interaction with the large-scale structure (up to 5Mpc), which may suggest that they have a common origin in their formation and evolution. We find that most of them belong to the outer parts of filaments, walls, and clusters, and generally differ from the void population of galaxies.