Search

Start Over Subject galaxies Validation Level 2
1771. Individual stars in Fornax dSph center
ID:
ivo://CDS.VizieR/J/A+A/523/A17
Title:
Individual stars in Fornax dSph center
Short Name:
J/A+A/523/A17
Date:
21 Oct 2021
Publisher:
CDS
Description:
For the first time we show the detailed, late-stage, chemical evolution history of a small nearby dwarf spheroidal galaxy in the Local Group. We present the results of a high-resolution (R~20000, {lambda}=5340-5620; 6120-6701) FLAMES/GIRAFFE abundance study at ESO/VLT of 81 photometrically selected, red giant branch stars in the central 25' of the Fornax dwarf spheroidal galaxy. We also carried out a detailed comparison of the effects of recent developments in abundance analysis (e.g., spherical models vs. plane-parallel) and the automation that is required to efficiently deal with such large data sets. We present abundances of alpha-elements (Mg, Si, Ca, and Ti), iron-peak elements (Fe, Ni, and Cr), and heavy elements (Y, Ba, La, Nd, and Eu).
1772. Infall motions in massive star-forming regions
ID:
ivo://CDS.VizieR/J/MNRAS/450/1926
Title:
Infall motions in massive star-forming regions
Short Name:
J/MNRAS/450/1926
Date:
21 Oct 2021
Publisher:
CDS
Description:
Massive star-forming regions with observed infall motions are good sites for studying the birth of massive stars. In this paper, 405 compact sources have been extracted from the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) compact sources that also have been observed in the Millimetre Astronomy Legacy Team 90-GHz (MALT90) survey during years 1 and 2. These observations are complemented with Spitzer GLIMPSE/MIPSGAL mid-IR survey data to help classify the elected star-forming clumps into three evolutionary stages: pre-stellar, proto-stellar and UCHII regions. The results suggest that 0.05g/cm^2^ is a reliable empirical lower bound for the clump surface densities required for massive-star formation to occur. The optically thick HCO^+^(1-0) and HNC(1-0) lines, as well as the optically thin N_2_H^+^(1-0) line were used to search for infall motions towards these sources. By analysing the asymmetries of the optically thick HCO^+^(1-0) and HNC(1-0) lines and the mapping observations of HCO^+^(1-0), a total of 131 reliable infall candidates have been identified. The HCO^+^(1-0) line shows the highest occurrence of obvious asymmetric features, suggesting that it may be a better infall motion tracer than other lines such as HNC(1-0). The detection rates of infall candidates towards pre-stellar, proto-stellar and UCHII clumps are 0.3452, 0.3861 and 0.2152, respectively. The relatively high detection rate of infall candidates towards UCHII clumps indicates that many UCHII regions are still accreting matter. The peak column densities and masses of the infall candidates, in general, display an increasing trend with progressing evolutionary stages. However, the rough estimates of the mass infall rate show no obvious variation with evolutionary stage.
1773. Infall motions in massive star-forming regions
ID:
ivo://CDS.VizieR/J/MNRAS/461/2288
Title:
Infall motions in massive star-forming regions
Short Name:
J/MNRAS/461/2288
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this work, we aim to characterize high-mass clumps with infall motions. We selected 327 clumps from the Millimetre Astronomy Legacy Team 90-GHz survey, and identified 100 infall candidates. Combined with the results of He et al. (2015, Cat. J/MNRAS/450/1926), we obtained a sample of 732 high-mass clumps, including 231 massive infall candidates and 501 clumps where infall is not detected. Objects in our sample were classified as pre-stellar, proto-stellar, HII or photodissociation region (PDR). The detection rates of the infall candidates in the pre-stellar, proto-stellar, HII and PDR stages are 41.2 per cent, 36.6 per cent, 30.6 per cent and 12.7 per cent, respectively. The infall candidates have a higher H_2_ column density and volume density compared with the clumps where infall is not detected at every stage. For the infall candidates, the median values of the infall rates at the pre-stellar, proto-stellar, HII and PDR stages are 2.6 x 10^-3^, 7.0x10^-3^, 6.5x10^-3^ and 5.5x10^-3^M_{sun}_/yr, respectively. These values indicate that infall candidates at later evolutionary stages are still accumulating material efficiently. It is interesting to find that both infall candidates and clumps where infall is not detected show a clear trend of increasing mass from the pre-stellar to proto-stellar, and to the HII stages. The power indices of the clump mass function are 2.04+/-0.16 and 2.17+/-0.31 for the infall candidates and clumps where infall is not detected, respectively, which agree well with the power index of the stellar initial mass function (2.35) and the cold Planck cores (2.0).
1774. Infrared extinction toward the Galactic Centre
ID:
ivo://CDS.VizieR/J/ApJ/737/73
Title:
Infrared extinction toward the Galactic Centre
Short Name:
J/ApJ/737/73
Date:
21 Oct 2021
Publisher:
CDS
Description:
We derive the extinction curve toward the Galactic center (GC) from 1 to 19um. We use hydrogen emission lines of the minispiral observed by ISO-SWS and SINFONI. The extinction-free flux reference is the 2cm continuum emission observed by the Very Large Array. Toward the inner 14"x20", we find an extinction of A_2.166um_=2.62+/-0.11, with a power-law slope of {alpha}=-2.11+/-0.06 shortward of 2.8um, consistent with the average near-infrared slope from the recent literature. At longer wavelengths, however, we find that the extinction is grayer than shortward of 2.8um. We find that it is not possible to fit the observed extinction curve with a dust model consisting of pure carbonaceous and silicate grains only, and the addition of composite particles, including ices, is needed to explain the observations. Combining a distance-dependent extinction with our distance-independent extinction, we derive the distance to the GC to be R_0_=7.94+/-0.65kpc. Toward Sgr A* (r<0.5"), we obtain A_H_=4.21+/-0.10, A_Ks_=2.42+/-0.10, and A_L'_=1.09+/-0.13.
1775. Infrared Luminosities of Local Galaxies
ID:
ivo://CDS.VizieR/J/PAZh/31/332
Title:
Infrared Luminosities of Local Galaxies
Short Name:
J/PAZh/31/332
Date:
21 Oct 2021
Publisher:
CDS
Description:
Based on data from 2MASS (<II/246>) we analyzed the infrared properties of 451 Local-Volume galaxies at distances D<=10Mpc.
1776. Infrared luminosity in GOODS fields
ID:
ivo://CDS.VizieR/J/A+A/528/A35
Title:
Infrared luminosity in GOODS fields
Short Name:
J/A+A/528/A35
Date:
21 Oct 2021
Publisher:
CDS
Description:
We derive the evolution of the infrared luminosity function (LF) over the last 4/5ths of cosmic time using deep 24um and 70um imaging of the GOODS North and South fields. We perform a stacking analysis to characterize the observed L_24_/(1+z) vs L_70_/(1+z) correlation. Then, using spectral energy distribution templates which best fit this correlation, we derive the infrared luminosity of individual sources from their 24um and 70um luminosities. We then compute the infrared LF at z=1.55+/-0.25 and z=2.05+/-0.25. The redshift evolution of the infrared LF from z=1.5 to z=2 is consistent with a luminosity evolution proportional to (1+z)^1.0+/-0.9^ combined with a density evolution proportional to (1+z)^-1.1+/-1.5^. At z=2, LIRGs are still the main contributors, at 49%, to the total comoving infrared luminosity density of the Universe while ULIRGs account for 17%.
1777. Infrared-luminous giants in M32
ID:
ivo://CDS.VizieR/J/AJ/104/1349
Title:
Infrared-luminous giants in M32
Short Name:
J/AJ/104/1349
Date:
21 Oct 2021
Publisher:
CDS
Description:
A previously unknown population of very luminous, red, asymptotic-giant-branch stars has been identified as a result of near-infrared (JHK) imaging in the dwarf elliptical galaxy M32. Situated above the tip of the normal first red giant branch, these stars are intrinsically brighter than the most luminous normal giants in old Galactic globular clusters by approximately 2 bolometric magnitudes. Moreover, they are a full bolometric magnitude brighter than the brightest giants observed in our own Galactic bulge. Several possible explanations for this population are examined, including old long-period variables, binary mergers, supermetallicity, and intermediate-age stars. It is suggested that the simplest explanation at present, is that M32 had a star formation episode less than about 5 billion years ago. These stars would then be the evolved extended asymptotic giant branch population resulting from that event (similar to those stars observed in the intermediate-age clusters in the Magellanic Clouds). This population may be similar to that in the M31 bulge, recently observed by Rich and Mould. The detection of a young component in M32 is of particular interest because historically, M32 has been a fiducial galaxy for population synthesis techniques. An understanding of M32 remains crucial for our understanding of distant and more luminous elliptical galaxies.
1778. Infrared massive stellar content of M83
ID:
ivo://CDS.VizieR/J/A+A/578/A100
Title:
Infrared massive stellar content of M83
Short Name:
J/A+A/578/A100
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a catalog of point sources in the field of M83. Sources were first cataloged that were found in both Spitzer IRAC 3.6-micron and 4.5-micron images. These were then supplemented with 5.8 and 8.0-micron photometry. Ground-based near-IR photometry in J and Ks-bands were extracted from imaging from the FourStar camera on the Baade Magellan Telescope at Las Campanas Observatory. Optical photometry was extracted from Hubble Space Telescope Wide Field Camera 3 observations of seven fields covering much of the bright disk region of M83.
1779. Infrared photometric study of Wolf-Rayet galaxies
ID:
ivo://CDS.VizieR/J/AJ/155/17
Title:
Infrared photometric study of Wolf-Rayet galaxies
Short Name:
J/AJ/155/17
Date:
21 Oct 2021
Publisher:
CDS
Description:
We collected observational data on 781 Wolf-Rayet (WR) galaxies from the literature to photometrically study their infrared properties measured by the 2MASS, WISE, IRAS, AKARI, and Herschel missions. It is found that in the 1-5 {mu}m range the radiations of WR galaxies are dominated by the free-free emissions from the stellar winds and the circumstellar dust from the late-type stars in the host galaxy. In the 5-22 {mu}m range, the radiation of WR galaxies is dominated by the free-free emissions and the synchrotron radiation from the central active galactic nucleus (AGN; but not always present). In the 22-140 {mu}m range, the radiations of WR galaxies are dominated by the free-free emissions and the star formation/starburst activities. In the 250-500 {mu}m range, the radiation of WR galaxies is dominated by the free-free emissions. In addition, the comparison with the non-WR galaxies is made. It is shown that some star formation WR galaxies have redder near-infrared colors than non-WR star-forming galaxies probably due to the gas emission in the near-infrared. In the 2-5 {mu}m region WR galaxies have redder colors due to the thermal emission from circumstellar dust of late-type stars and the enhanced gas emission. In the 5-22 {mu}m region, both WR galaxies and non-WR galaxies have similar behavior, indicative of having similar free-free emission as the dominant radiation. In the 25-140 {mu}m region, both types of galaxies also have similar behavior, indicative of having free-free emission from the stellar winds or the thermal radiation from the starburst/star formation as the dominant radiation.
1780. Infrared Photometry and 21cm data for nearby galaxies
ID:
ivo://CDS.VizieR/VII/75
Title:
Infrared Photometry and 21cm data for nearby galaxies
Short Name:
VII/75
Date:
21 Oct 2021
Publisher:
CDS
Description:
The catalogue is a compilation of magnitudes at 1.6um, 21cm velocity widths, and related data on 307 nearby galaxies.

Limit your search

more »

more »

more »

more »