Search

Start Over Subject galaxies
1841. IR sources in the NGC 5291 system
ID:
ivo://CDS.VizieR/J/ApJ/640/768
Title:
IR sources in the NGC 5291 system
Short Name:
J/ApJ/640/768
Date:
21 Oct 2021
Publisher:
CDS
Description:
We observed two faint tidal dwarf galaxies (TDGs), NGC 5291 N and NGC 5291 S, with the Infrared Spectrograph on the Spitzer Space Telescope. We detect strong polycyclic aromatic hydrocarbon (PAH) emission at 6.2, 7.7, 8.6, 11.3, 12.6, and 16.5{mu}m, which match models of groups of 100 carbon atoms with an equal mixture of neutral and ionized PAHs.
1842. IR sources spectroscopy in the AKARI NEP
ID:
ivo://CDS.VizieR/J/ApJS/207/37
Title:
IR sources spectroscopy in the AKARI NEP
Short Name:
J/ApJS/207/37
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present spectra of 1796 sources selected in the AKARI North Ecliptic Pole Wide Survey field, obtained with MMT/Hectospec and WIYN/Hydra, for which we measure 1645 redshifts. We complemented the generic flux-limited spectroscopic surveys at 11 {mu}m and 15 {mu}m, with additional sources selected based on the MIR and optical colors. In MMT/Hectospec observations, the redshift identification rates are ~80% for objects with R < 21.5 mag. On the other hand, in WIYN/Hydra observations, the redshift identification rates are ~80% at R magnitudes brighter than 19 mag. The observed spectra were classified through the visual inspection or from the line diagnostics. We identified 1128 star-forming or absorption-line-dominated galaxies, 198 Type-1 active galactic nuclei (AGNs), 8 Type-2 AGNs, 121 Galactic stars, and 190 spectra in unknown category due to low signal-to-noise ratio. The spectra were flux-calibrated but to an accuracy of 0.1-0.18dex for most of the targets and worse for the remainder. We derive star formation rates (SFRs) from the mid-infrared fluxes or from the optical emission lines, showing that our sample spans an SFR range of 0.1 to a few hundred M_{sun}_/yr. We find that the extinction inferred from the difference between the IR and optical SFR increases as the IR luminosity increases but with a large scatter.
1843. IR spectra and SEDs for starbursts and AGNs
ID:
ivo://CDS.VizieR/J/ApJ/730/19
Title:
IR spectra and SEDs for starbursts and AGNs
Short Name:
J/ApJ/730/19
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present spectroscopic results for all galaxies observed with the Spitzer Infrared Spectrograph (IRS) that also have total infrared fluxes f_IR_ measured with the Infrared Astronomical Satellite (IRAS), also using AKARI photometry when available. Infrared luminosities and spectral energy distributions (SEDs) from 8um to 160um are compared to polycyclic aromatic hydrocarbon emission from starburst galaxies or mid-infrared dust continuum from active galactic nuclei (AGNs) at rest-frame wavelengths ~8um. A total of 301 spectra are analyzed for which IRS and IRAS include the same unresolved source, as measured by the ratio f_{nu}_(IRAS 25um)/f_{nu}_(IRS 25um). Sources have 0.004<z<0.34 and 42.5<logL_IR_<46.8(erg/s) and cover the full range of starburst galaxy and AGN classifications.
1844. IR spectral of 4 Ae/Be Herbig stars
ID:
ivo://CDS.VizieR/J/A+A/623/A135
Title:
IR spectral of 4 Ae/Be Herbig stars
Short Name:
J/A+A/623/A135
Date:
21 Oct 2021
Publisher:
CDS
Description:
In the interstellar medium, carbon (nano-)grains are a major component of interstellar dust. This solid phase is more vulnerable to processing and destruction than its silicate counterpart. It exhibits a complex, size-dependent evolution that is due to interactions within different radiative and dynamical environments. Infrared signatures of these carbon nano-grains are seen in a large number of discs around Herbig HAeBe stars. We probe the composition and evolution of carbon nano-grains at the surface of (pre-)transitional proto-planetary discs around Herbig stars. We present spatially resolved infrared emission spectra obtained with the Nasmyth Adaptive Optics System (NAOS) Near-Infrared Imager and Spectrograph (CONICA) at the Very Large Telescope (VLT) in the 3-4 microns range with a spatial resolution of 0.1-arcsec, which allowed us to trace aromatic, olefinic, and aliphatic bands that are attributed to sub-nanometer hydrocarbon grains. We applied a Gaussian fitting to analyse the observed spectral signatures. Finally, we propose an interpretation in the framework of theThe Heterogeneous dust Evolution Model of Interstellar Solids (THEMIS). We show the presence of several spatially extended spectral features that are related to aromatic and aliphatic hydrocarbon material in discs around Herbig stars, from 10 to 50-100au, and even in inner gaps that are devoid of large grains. The correlation and constant intensity ratios between aliphatic and aromatic CH stretching bands suggests a common nature of the carriers. Given their expected high destruction rates through UV photons, our observations suggest that they are continuously replenished at the disc surfaces.
1845. IR survey of brightest cluster galaxies I.
ID:
ivo://CDS.VizieR/J/ApJS/176/39
Title:
IR survey of brightest cluster galaxies I.
Short Name:
J/ApJS/176/39
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report on an imaging survey with the Spitzer Space Telescope of 62 brightest cluster galaxies (BCGs) with optical line emission. These galaxies are located in the cores of X-ray luminous clusters selected from the ROSAT All-Sky Survey. We find that about half of these sources have a sign of excess infrared emission; 22 objects out of 62 are detected at 70um, 18 have 8/5.8um flux ratios above 1.0 and 28 have 24/8um flux ratios above 1.0. Altogether 35 of 62 objects in our survey exhibit at least one of these signs of infrared excess. Four galaxies with infrared excesses have a 4.5/3.6um flux ratio indicating the presence of hot dust, and/or an unresolved nucleus at 8um. Three of these have high measured [OIII](5007{AA})/H{beta} flux ratios suggesting that these four, Abell 1068, Abell 2146, Zwicky 2089, and R0821+07, host dusty active galactic nuclei (AGNs). Nine objects (including the four hosting dusty AGNs) have infrared luminosities greater than 10^11^L_{sun}_ and so can be classified as luminous infrared galaxies (LIRGs). Excluding the four systems hosting dusty AGNs, the excess mid-infrared emission in the remaining brightest cluster galaxies is likely related to star formation.
1846. IRTF J-band spectrum of Mrk 231
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.
1847. IRX-{beta} relation of HII regions in NGC628
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.
1848. ISLAndS project. III. Variable stars
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.
1849. ISOCAM 14.3{mu}m Deep Survey in Lockman Hole
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.
1850. ISOCAM obs. of very deep IRAS 60um sources
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.

Limit your search

more »

more »

more »

more »

  • 24,327
  • 11