- 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.
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1272. 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/J/A+A/357/219
- Title:
- ISOCAM observations in Cha I.
- Short Name:
- J/A+A/357/219
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of an ISOCAM survey of the Chamaeleon I dark cloud conducted in two broad-band filters at 6.7 and 14.3{mu}m. In an area of 0.59deg^2^. we have detected a total of 282 mid-IR sources with 103 sources observed in both filters. Combining the ISOCAM observations with the I, J, and K_s_ data obtained with DENIS, we have found 108 pre-main-sequence (PMS) stars in the region, of which 34 were previously unidentified. Several of these newly discovered young stellar objects are relatively faint suggesting a population in Cha I of very low mass objects that probably includes brown dwarfs in their early contraction phases. Finally, most of the PMS stars show the spectral index computed between 2.2 and 14.3{mu}m typical of Class II sources. The luminosity function (LF) derived for our detected PMS stars is discussed.
- ID:
- ivo://CDS.VizieR/J/A+A/372/173
- Title:
- ISOCAM observations of the rho Ophiuchi cloud
- Short Name:
- J/A+A/372/173
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- File table1 contains the list of the 212 ISOCAM sources recognized as members of the rho Ophiuchi embedded cluster. It lists their J2000 coordinates, flux densities at 6.7 and 14.3 micron and associated rms uncertainties, as well as the corresponding near-infrared identifications and the adopted IR classes (Class I, II or III).
- ID:
- ivo://CDS.VizieR/J/A+A/458/789
- Title:
- ISOCAM survey of Serpens/G3-G6
- Short Name:
- J/A+A/458/789
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from an ISOCAM survey in the two broadband filters LW2 (5-8.5um) and LW3 (12-18um) of a 19'x16' field called Serp_NH3 centred on the optical group Serpens/G3-G6. A total of 186 sources were detected in the 6.7um band and/or the 14.3um band to a limiting sensitivity of ~2mJy. These have been cross-correlated with the 2MASS catalogue and are all listed in table1. Deep follow-up photometry in the Ks band obtained with Arnica at the Nordic Optical Telescope (NOT) is listed in table2. Deep L' band photometry of selected sources using SIRCA at the NOT is listed in table3. Continuum emission at 1.3mm and 3.6cm was observed with IRAM and VLA, respectively, and deep imaging in the 2.12um S(1) line of H2 was obtained with NOTCam at the NOT. We find strong evidence for a stellar population of 31 Class II sources (listed in table5), 5 flat-spectrum sources, 5 Class I sources (listed in table4), and two Class 0 sources. Our method does not sample the Class III sources.
- ID:
- ivo://CDS.VizieR/J/A+A/421/623
- Title:
- ISOCAM survey of YSOs in Serpens Cloud Core
- Short Name:
- J/A+A/421/623
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from an ISOCAM survey in the two broad band filters LW2 (5-8.5{mu}m) and LW3 (12-18{mu}m) of a 0.13 square degree coverage of the Serpens Main Cloud Core. A total of 392 sources were detected in the 6.7{mu}m band and 139 in the 14.3{mu}m band to a limiting sensitivity of ~2mJy. We identified 53 Young Stellar Objects (YSOs) with mid-IR excess from the single colour index [14.3/6.7], and 8 additional YSOs from the H-K/K-m_6.7_ diagram. Only 32 of these 61 sources were previously known to be YSO candidates.
- ID:
- ivo://CDS.VizieR/J/A+A/365/409
- Title:
- ISO continuum observations of quasars
- Short Name:
- J/A+A/365/409
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Eight luminous quasars with -30<M_B_<-27 at z=1.4-3.7 have been observed in the mid- and far-infrared using ISO. All the quasars have been detected in the mid-infrared bands of ISOCAM, while no far-infrared detections have been made with ISOPHOT. SEDs (Spectral Energy Distributions) from the UV to far-infrared have been obtained while supplementing ISO observations with photometry in the optical and near-infrared made from the ground within 17 months. The SEDs are compared with the MED (Mean spectral Energy Distributions) of low-redshift quasars with -27<M_B_<-22. It is shown that our far-infrared observations were limited by confusion noise due to crowded sources.
- ID:
- ivo://CDS.VizieR/J/A+A/403/141
- Title:
- ISOGAL sources in intermediate bulge fields
- Short Name:
- J/A+A/403/141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of ISOGAL sources in the "intermediate" galactic bulge (|l|<2{deg}, |b|~1{deg}-4{deg}), observed by ISOCAM at 7 and 15{mu}m. In combination with near-infrared (I, J, Ks) data of DENIS survey, complemented by 2MASS data, we discuss the nature of the ISOGAL sources, their luminosities, the interstellar extinction and the mass-loss rates. A large fraction of the 1464 detected sources at 15{mu}m are AGB stars above the RGB tip, a number of them show an excess in ([7]-[15])_0_ and (Ks-[15])_0_ colours, characteristic of mass-loss. The latter, especially (Ks-[15])_0_, provide estimates of the mass-loss rates and show their distribution in the range 10^-8^ to 10^-5^M_{sun}_/yr.
