- 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.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+AS/146/437
- Title:
- IR spectra of oxygen-rich evolved stars
- Short Name:
- J/A+AS/146/437
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have analyzed the 8-13.5{mu}m UKIRT CGS3 spectra of 142 M-type stars including 80 oxygen-rich AGB stars and 62 red supergiants, with a view to understanding the differences and similarities between the dust features of these stars. We have classified the spectra into groups according to the observed appearance of the infrared features.
- ID:
- ivo://CDS.VizieR/J/ApJ/769/149
- Title:
- IR spectroscopy in Orion A: transitional disks
- Short Name:
- J/ApJ/769/149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Transitional disks are protoplanetary disks around young stars, with inner holes or gaps which are surrounded by optically thick outer, and often inner, disks. Here we present observations of 62 new transitional disks in the Orion A star-forming region. These were identified using the Spitzer Space Telescope's Infrared Spectrograph and followed up with determinations of stellar and accretion parameters using the Infrared Telescope Facility's SpeX. We combine these new observations with our previous results on transitional disks in Taurus, Chamaeleon I, Ophiuchus, and Perseus, and with archival X-ray observations. This produces a sample of 105 transitional disks of "cluster" age 3Myr or less, by far the largest hitherto assembled. We use this sample to search for trends between the radial structure in the disks and many other system properties, in order to place constraints on the possible origins of transitional disks. We see a clear progression of host-star accretion rate and the different disk morphologies. We confirm that transitional disks with complete central clearings have median accretion rates an order of magnitude smaller than radially continuous disks of the same population. Pre-transitional disks--those objects with gaps that separate inner and outer disks--have median accretion rates intermediate between the two. Our results from the search for statistically significant trends, especially related to dM/dt, strongly support that in both cases the gaps are far more likely to be due to the gravitational influence of Jovian planets or brown dwarfs orbiting within the gaps, than to any of the photoevaporative, turbulent, or grain-growth processes that can lead to disk dissipation. We also find that the fraction of Class II YSOs which are transitional disks is large, 0.1-0.2, especially in the youngest associations.
- ID:
- ivo://CDS.VizieR/J/ApJS/226/11
- Title:
- IR spectroscopy of AGN & starbursts
- Short Name:
- J/ApJS/226/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A sample of 379 extragalactic sources is presented that has mid-infrared, high-resolution spectroscopy from the Spitzer Infrared Spectrograph (IRS) and also spectroscopy of the [CII]158{mu}m line from the Herschel Photodetector Array Camera and Spectrometer (PACS). The emission line profiles of [NeII]12.81{mu}m, [NeIII]15.55{mu}m, and [CII]158{mu}m are presented, and intrinsic line widths are determined (full width half maximum of Gaussian profiles after instrumental correction). All line profiles, together with overlays comparing the positions of PACS and IRS observations, are made available in the Cornell Atlas of Spitzer IRS Sources (CASSIS). Sources are classified from active galactic nucleus (AGN) to starburst based on equivalent widths of the 6.2{mu}m polycyclic aromatic hydrocarbon feature. It is found that intrinsic line widths do not change among classifications for [CII], with median widths of 207km/s for AGNs, 248km/s for composites, and 233km/s for starbursts. The [NeII] line widths also do not change with classification, but [NeIII] lines are progressively broader from starburst to AGN. A few objects with unusually broad lines or unusual redshift differences in any feature are identified.
- ID:
- ivo://CDS.VizieR/J/ApJ/670/1115
- Title:
- IRS spectra at 38 positions in Galactic center
- Short Name:
- J/ApJ/670/1115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Spitzer IRS spectra (R~600, 10-38um) of 38 positions in the Galactic center, all at the same Galactic longitude and spanning +/-0.3{deg} in latitude. Our positions include the Arches Cluster, the Arched Filaments, regions near the Quintuplet Cluster, the "Bubble" lying along the same line of sight as the molecular cloud G0.11-0.11, and the diffuse interstellar gas along the line of sight at higher Galactic latitudes.
- 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+A/620/A32
- Title:
- IRS spectra of 22 O7-B5 I-V stars
- Short Name:
- J/A+A/620/A32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of the analysis of a sample of 22 stars of spectral types from O7 to B5 and luminosity classes I-V for which spectra from the Infrared Spectrograph (IRS) of Spitzer are available. The IRS spectra of these stars are examined for signs of excess infrared (IR) emission by comparison with stellar atmospheric spectra. We find that the spectra of half of the studied stars are dominated by excess emission in the far-IR, including all six super- and bright giants. In order to examine the origin of the far-IR excess, we supplement the Spitzer data with optical high-resolution echelle spectroscopy ({lambda}{Delta}{lambda}~10^5^), near-IR high-contrast coronagraphic imaging taken with the SPHERE instrument at VLT with a spatial resolution of 0.05", and WISE and Herschel photometry. In the optical region, we detect various absorption and emission lines (H{alpha}, CIII, and NIII) irrespective of the far-IR excess. Pfund{alpha} and Humphrey{alpha} lines are observed at the same time as the far-IR excess. These lines are stronger in stars with far-IR excess than in stars without excess. A scattered-light disk in the central r<2.5" region of the far-IR excess stars HD149404, HD151804, and HD154368 can be excluded from H band imaging down to a 1{sigma} contrast of F(r)/F*~10^-6^. The far-IR excess is fit either by a free-free component from ionized gas as for the winds of hot stars or a large (1pc) circumstellar dust shell. The putative dust envelopes required to explain the excess have a visual extinction as low as a few hundred micro-mag.
- ID:
- ivo://CDS.VizieR/J/ApJ/705/89
- Title:
- IRS spectra of solar-type stars
- Short Name:
- J/ApJ/705/89
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have observed 152 nearby solar-type stars with the Infrared Spectrometer (IRS) on the Spitzer Space Telescope. Including stars that met our criteria but were observed in other surveys, we get an overall success rate for finding excesses in the long-wavelength IRS band (30-34um) of 11.8%+/-2.4%. The success rate for excesses in the short-wavelength band (8.5-12um) is ~1% including sources from other surveys. Two stars (HD 40136 and HD 10647) show weak evidence for spectral features; the excess emission in the other systems is featureless. For most stars with excesses, we detect an excess at both IRS and Multiband Imaging Photometer for Spitzer (MIPS) wavelengths. Only three stars in this sample show a MIPS 70um excess with no IRS excess, implying that very cold dust is rare around solar-type stars.
- ID:
- ivo://CDS.VizieR/J/AJ/151/146
- Title:
- IRS spectra with features of crystalline silicates
- Short Name:
- J/AJ/151/146
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The crystalline silicate features are mainly reflected in infrared bands. The Spitzer Infrared Spectrograph (IRS) collected numerous spectra of various objects and provided a big database to investigate crystalline silicates in a wide range of astronomical environments. We apply the manifold ranking algorithm to perform a systematic search for the spectra with crystalline silicate features in the Spitzer IRS Enhanced Products available. In total, 868 spectra of 790 sources are found to show the features of crystalline silicates. These objects are cross-matched with the SIMBAD database as well as with the Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST)/DR2 (Luo et al. 2016, Cat. V/149). The average spectrum of young stellar objects shows a variety of features dominated either by forsterite or enstatite or neither, while the average spectrum of evolved objects consistently present dominant features of forsterite in AGB, OH/IR, post-AGB, and planetary nebulae. They are identified optically as early-type stars, evolved stars, galaxies and so on. In addition, the strength of spectral features in typical silicate complexes is calculated. The results are available through CDS for the astronomical community to further study crystalline silicates.
- ID:
- ivo://CDS.VizieR/J/A+A/397/177
- Title:
- IR star clusters and stellar groups catalog
- Short Name:
- J/A+A/397/177
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We compiled a catalogue of infrared star clusters in the Galaxy, which are most of them embedded. It condenses the growing literature information. We also include in the sample infrared stellar groups which are less dense than star clusters, such as those embedded in the dark clouds Taurus-Auriga and Chamaleon I. We provide galactic and equatorial coordinates, angular dimensions, different designations and related objects such as nebulae. A total of 189 infrared clusters and 87 embedded stellar groups are included. A fraction of 25% of the embedded clusters are projected close to each other in pair or triplet systems, indicating that multiplicity plays an important role in star cluster formation.
