- ID:
- ivo://CDS.VizieR/J/ApJS/214/23
- Title:
- IR spectra and photometry of z<0.5 quasars
- Short Name:
- J/ApJS/214/23
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As a step toward a comprehensive overview of the infrared (IR) diagnostics of the central engines and host galaxies of quasars at low redshift, we present Spitzer Space Telescope spectroscopic (5-40{mu}m) and photometric (24, 70, and 160{mu}m) measurements of all Palomar-Green (PG) quasars at z<0.5 and Two Micron All Sky Survey (2MASS) quasars at z<0.3. We supplement these data with Herschel measurements at 160{mu}m. The sample is composed of 87 optically selected PG quasars and 52 near-IR-selected 2MASS quasars. Here we present the data, measure the prominent spectral features, and separate emission due to star formation from that emitted by the dusty circumnuclear torus. We find that the mid-IR (5-30{mu}m) spectral shape for the torus is largely independent of quasar IR luminosity with scatter in the spectral energy distribution (SED) shape of <~0.2dex. Except for the silicate features, no large difference is observed between PG (unobscured --silicate emission) and 2MASS (obscured --silicate absorption) quasars. Only mild silicate features are observed in both cases. When in emission, the peak wavelength of the silicate feature tends to be longer than 9.7{mu}m, possibly indicating effects on grain properties near the active galactic nucleus. The IR color is shown to correlate with the equivalent width of the aromatic features, indicating that the slope of the quasar mid- to far-IR SED is to first order driven by the fraction of radiation from star formation in the IR bands.
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Search Results
- 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.
- ID:
- ivo://CDS.VizieR/J/A+A/405/531
- Title:
- IR spectra of ISOGAL sources in Galactic Bulge
- Short Name:
- J/A+A/405/531
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work we present near-IR spectra (HK-band) of a sample of 107 sources with mid-IR excesses at 7 and 15{mu}m detected during the ISOGAL survey. Making use of the DENIS interstellar extinction map from Schultheis et al. (1999, Cat. <J/A+A/349/L69>) we derive luminosities and find that the Mbol vs. ^12^CO and Mbol vs. H_2_O diagrams are powerful tools for identifying supergiants, AGB stars, giants and young stellar objects. The majority of our sample are AGB stars (~80%) while we find four good supergiant candidates, nine young stellar objects and 12 RGB candidates. We have used the most recent K_0_-[15] relation by Jeong et al. (2002, in Mass-losing Pulsating tars and their Circumstellar Matter, ed. Y. Nakasa, M. Honma, & M. Sekiin) based on recent theoretical modeling of dust formation of AGB stars to determine mass-loss rates. The mass-loss rates of the supergiants are comparable with those in the solar neighbourhood while the long-period Variables cover a mass-loss range from -5<log(dM/dt)<-7. The red giant candidates lie at the lower end of the mass-loss rate range between -6.5<log(dM/dt)<-9. We used the equivalent width of the CO bandhead at 2.3 mum, the NaI doublet and the CaI triplet to estimate metallicities using the relation by Ramirez et al. (2000ApJ...537..205R). The metallicity distribution of the ISOGAL objects shows a mean [Fe/H]~-0.25dex with a dispersion of +/-0.40dex which is in agreement with the values of Ramirez et al. (2000ApJ...537..205R) for Galactic Bulge fields between b=-4{deg} and b=-1.3{deg}. A comparison with the solar neighbourhood sample of Lancon & Wood (2000, Cat. <J/A+AS/146/217>) shows that our sample is ~0.5dex more metal-rich on average.
- ID:
- ivo://CDS.VizieR/J/ApJ/683/114
- Title:
- IRS spectra of faint IRAS sources
- Short Name:
- J/ApJ/683/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Extragalactic sources from the IRAS Faint Source Catalog (FSC) that have the optically faintest magnitudes (E>~18) were selected by spatial coincidence with a source in the FIRST radio survey, and 28 of these sources have been observed with the Infrared Spectrograph on Spitzer (IRS). While an infrared source is always detected with the IRS at the FIRST position, only ~50% of the infrared sources are real FSC detections, as estimated from the number of sources for which the f_v_(25um) determined with the IRS is fainter than the sensitivity limit for the FSC. Sources have 0.12<z<1.0 and luminosities 43.3<log[{nu}L_{nu}_(5.5um)]<46.7erg/s, encompassing the range from local ULIRGs to the most luminous sources discovered by Spitzer at z~2. Detectable PAH features are found in 15 of the sources (54%), and measurable silicate absorption is found in 19 sources (68%); both PAH emission and silicate absorption are present in 11 sources. PAH luminosities are used to determine the starburst fraction of bolometric luminosity, and model predictions for a dusty torus are used to determine the AGN fraction of luminosity in all sources based on vL_v_(5.5um). Approximately half of the sources have luminosity dominated by an AGN and approximately half by a starburst.
- ID:
- ivo://CDS.VizieR/J/A+AS/93/61
- Title:
- IR Stellar Population in Baade's window
- Short Name:
- J/A+AS/93/61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 2.2um (K) scan (table1) was made on the Mt. Stromlo 1.9m telescope with the MSO IR-photometer, during several observation sessions in 1981, at sideral rate with a 12arcsec aperture; the rows of the scan were spaced by 6arcsec in declination, and were on the average 65arcmin long. Detailed JHK photometry of a sample of the brightest sources (table 2) was obtained during later observing sessions in 1981 and 1982. The photometric results are given in the AAO system (Jones & Hyland, 1980MNRAS.192..359J)
- 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.
3077. IRTS carbon stars
- ID:
- ivo://CDS.VizieR/J/PASP/117/199
- Title:
- IRTS carbon stars
- Short Name:
- J/PASP/117/199
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have identified 139 cool carbon stars in the near-infrared spectrophotometric survey of the Infrared Telescope in Space (IRTS) from the conspicuous presence of molecular absorption bands at 1.8, 3.1, and 3.8{mu}m. Among them, 14 are new bright (K~4.0-7.0) Carbon stars. We find a trend relating the 3.1{mu}m band strength to the (K-L') color index, which is known to correlate with mass-loss rate. This could be an effect of a relation between the depth of the 3.1{mu}m feature and the degree of development of the extended stellar atmosphere where dust starts to form.
- ID:
- ivo://CDS.VizieR/J/AJ/155/99
- Title:
- IR variability among YSOs in the Serpens South cluster
- Short Name:
- J/AJ/155/99
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a time-variability study of young stellar objects (YSOs) in the Serpens South cluster performed at 3.6 and 4.5 {mu}m with the Spitzer Space Telescope; this study is part of the Young Stellar Object VARiability project. We have collected light curves for more than 1500 sources, including 85 cluster members, over 38 days. This includes 44 class I sources, 19 sources with flat spectral energy distributions (SEDs), 17 class II sources, and five diskless YSO candidates. We find a high variability fraction among embedded cluster members of ~70%, whereas young stars without a detectable disk display no variability. We detect periodic variability for 32 sources with periods primarily in the range of 0.2-14 days and a subset of fast rotators thought to be field binaries. The timescale for brightness changes are shortest for stars with the most photospheric SEDs and longest for those with flat or rising SEDs. While most variable YSOs become redder when fainter, as would be expected from variable extinction, about 10% get bluer as they get fainter. One source, SSTYSV J183006.13-020108.0, exhibits "cyclical" color changes.
- 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/II/197
- Title:
- ISM towards IC 348 and Per OB2
- Short Name:
- II/197
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The relationship between interstellar extinction and distance in the direction of dark clouds in the areas around the open cluster IC 348 and the association Per OB2 is determined using the results of photoelectric photometry of 189 stars in the Vilnius photometric system.