- ID:
- ivo://CDS.VizieR/J/A+A/609/A102
- Title:
- Inner/outer HII regions: galaxy sample
- Short Name:
- J/A+A/609/A102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using integral field spectroscopy (IFS) observations we aim to perform a systematic study and comparison of two inner and outer HII regions samples. The spatial resolution of the IFS, the number of objects and the homogeneity and coherence of the observations allow a complete characterization of the main observational properties and differences of the regions. We analyzed a sample of 725 inner HII regions and a sample of 671 outer HII regions, all of them detected and extracted from the observations of a sample of 263 nearby, isolated, spiral galaxies observed by the CALIFA survey. We find that inner HII regions show smaller equivalent widths, greater extinction and luminosities, along with greater values of [NII] {lambda}6583/H{alpha} and [OII] {lambda}3727/[OIII] {lambda}5007 emission-line ratios, indicating higher metallicities and lower ionization parameters. Inner regions have also redder colors and higher photometric and ionizing masses, although Mion/Mphot is slightly higher for the outer regions. This work shows important observational differences between inner and outer HII regions in star forming galaxies not previously studied in detail. These differences indicate that inner regions have more evolved stellar populations and are in a later evolution state with respect to outer regions, which goes in line with the inside-out galaxy formation paradigm.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/504/681
- Title:
- Integrated BVJHKs for 650 open clusters
- Short Name:
- J/A+A/504/681
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We determine the integrated magnitudes and colours of 650 clusters in optical (BV) and the near-infrared (JHKs) passbands and construct the luminosity functions of the Galactic open clusters in these passbands.
- ID:
- ivo://CDS.VizieR/J/MNRAS/403/1491
- Title:
- Integrated magnitudes of synthetic star clusters
- Short Name:
- J/MNRAS/403/1491
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents integrated magnitudes and colours for synthetic clusters. The integrated parameters have been obtained for the whole cluster population as well as for the main-sequence (MS) population of star clusters. We have also estimated observed integrated magnitudes and colours of the MS population of galactic open clusters, Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) star clusters.
- ID:
- ivo://CDS.VizieR/J/ApJ/846/159
- Title:
- Interferometric CO obs. of 126 CALIFA galaxies
- Short Name:
- J/ApJ/846/159
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present interferometric CO observations, made with the Combined Array for Millimeter-wave Astronomy (CARMA) interferometer, of galaxies from the Extragalactic Database for Galaxy Evolution survey (EDGE). These galaxies are selected from the Calar Alto Legacy Integral Field Area (CALIFA) sample, mapped with optical integral field spectroscopy. EDGE provides good-quality CO data (3{sigma} sensitivity {Sigma}_mol_~11M_{sun}/pc^2^ before inclination correction, resolution ~1.4kpc) for 126 galaxies, constituting the largest interferometric CO survey of galaxies in the nearby universe. We describe the survey and data characteristics and products, then present initial science results. We find that the exponential scale lengths of the molecular, stellar, and star-forming disks are approximately equal, and galaxies that are more compact in molecular gas than in stars tend to show signs of interaction. We characterize the molecular-to-stellar ratio as a function of Hubble type and stellar mass and present preliminary results on the resolved relations between the molecular gas, stars, and star-formation rate. We then discuss the dependence of the resolved molecular depletion time on stellar surface density, nebular extinction, and gas metallicity. EDGE provides a key data set to address outstanding topics regarding gas and its role in star formation and galaxy evolution, which will be publicly available on completion of the quality assessment.
- ID:
- ivo://CDS.VizieR/J/AJ/160/37
- Title:
- Intergalac. medium opacity from Lyman-break galaxies
- Short Name:
- J/AJ/160/37
- Date:
- 08 Dec 2021
- Publisher:
- CDS
- Description:
- We measure the effective opacity ({tau}_eff_) of the intergalactic medium from the composite spectra of 281 Lyman-break galaxies in the redshift range 2<~z<~3. Our spectra are taken from the COSMOS Ly{alpha} Mapping And Tomographic Observations survey derived from the Low Resolution Imaging Spectrometer on the W.M. Keck I telescope. We generate composite spectra in two redshift intervals and fit them with spectral energy distribution (SED) models composed of simple stellar populations. Extrapolating these SED models into the Ly{alpha} forest, we measure the effective Ly{alpha} opacity ({tau}_eff_) in the 2.02<~z<~2.44 range. At z=2.22, we estimate {tau}_eff_=0.159{+/-}0.001 from a power-law fit to the data. These measurements are consistent with estimates from quasar analyses at z<2.5 indicating that the systematic errors associated with normalizing quasar continua are not substantial. We provide a Gaussian processes model of our results and previous {tau}_eff_ measurements that describes the steep redshift evolution in {tau}_eff_ from z=1.5-4.
- ID:
- ivo://CDS.VizieR/J/ApJ/726/19
- Title:
- Intermediate-mass stars in IC 1805
- Short Name:
- J/ApJ/726/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of a study of the intermediate- and high-mass stars in the young, rich star-forming complex IC 1805, based on a combination of optical, near-infrared, and mid-infrared photometry, and classification spectra. These data provide the basis for characterizing the masses and ages for stars more massive than ~2M_{sun}_ and enable a study of the frequency and character of circumstellar disks associated with intermediate- and high-mass stars. Optically thick accretion disks among stars with masses 2<M/M_{sun}_<4 are rare (~2% of members) and absent among more massive stars. A larger fraction (~10%) of stars with masses 2<M/M_{sun}_<4 appear to be surrounded by disks that have evolved from the initial optically thick accretion phase. We identify four classes of such disks. These classes are based on spectral energy distributions (SEDs) of excess emission above photospheric levels: disks that are (1) optically thin based on the magnitude of the observed excess emission from 2 to 24um, (2) optically thin in their inner regions (r<20AU) and optically thick in their outer regions, (3) exhibit empty inner regions (r<10AU) and optically thin emission in their outer regions, and (4) exhibit empty inner regions and optically thick outer regions. We discuss, and assess the merits and liabilities of, proposed explanations for disks exhibiting these SED types and suggest additional observations that would test these proposals.
- ID:
- ivo://CDS.VizieR/J/BaltA/11/1
- Title:
- Interstellar extinction curves of OB stars
- Short Name:
- J/BaltA/11/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The paper presents a collection of 436 extinction curves covering the whole available range of wavelengths from satellite UV to near-IR. The data were taken from the ANS photometric catalogue (Cat. <II/97>) and from the compilations of IR photometric measurements. The data curves have been obtained with the aid of "artificial standards" Papaj et al. (1993A&A...273..575P) and Wegner (1994MNRAS.270..229W, 1995, Interstellar Absorption Structures in the Direction of Nearby OB stars, Wyd. Uczelniane WSP, Bydgoszcz, p. 1-383). The visual magnitudes and spectral classifications of O and B type stars with E_B-V_>=0.05 were taken from the SIMBAD database. The curves are given in the form of plots and tables E_{lambda}-V_/E_B-V_ versus 1/{lambda}. The observed variety of extinction laws among slightly reddened stars is apparently due to the various physical parameters of interstellar clouds.
- ID:
- ivo://CDS.VizieR/J/ApJS/208/9
- Title:
- Intrinsic colors and temperatures of PMS stars
- Short Name:
- J/ApJS/208/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the intrinsic colors and temperatures of 5-30 Myr old pre-main-sequence (pre-MS) stars using the F0- through M9-type members of nearby, negligibly reddened groups: the {eta} Cha cluster, the TW Hydra Association, the {beta} Pic Moving Group, and the Tucana-Horologium Association. To check the consistency of spectral types from the literature, we estimate new spectral types for 52 nearby pre-MS stars with spectral types F3 through M4 using optical spectra taken with the SMARTS 1.5 m telescope. Combining these new types with published spectral types and photometry from the literature (Johnson-Cousins BVI_C_, 2MASS JHK_S_ and WISE W1, W2, W3, and W4), we derive a new empirical spectral type-color sequence for 5-30 Myr old pre-MS stars. Colors for pre-MS stars match dwarf colors for some spectral types and colors, but for other spectral types and colors, deviations can exceed 0.3 mag. We estimate effective temperatures (T_eff_) and bolometric corrections (BCs) for our pre-MS star sample through comparing their photometry to synthetic photometry generated using the BT-Settl grid of model atmosphere spectra. We derive a new T_eff_ and BC scale for pre-MS stars, which should be a more appropriate match for T Tauri stars than often-adopted dwarf star scales. While our new T_eff_ scale for pre-MS stars is within =~100K of dwarfs at a given spectral type for stars <G5, for G5 through K6, the pre-MS stars are ~250 K cooler than their MS counterparts. Lastly, we present (1) a modern T_eff_, optical/IR color, and BC sequence for O9V-M9V MS stars based on an extensive literature survey, (2) a revised Q-method relation for dereddening UBV photometry of OB-type stars, and (3) introduce two candidate spectral standard stars as representatives of spectral types K8V and K9V.
- ID:
- ivo://CDS.VizieR/J/MNRAS/407/2475
- Title:
- Ionized gas in E/S0 galaxies with dust lanes
- Short Name:
- J/MNRAS/407/2475
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of multicolour observations of 30 E/S0 galaxies with dust lanes. For each galaxy we obtained broad-band images and narrow-band images using interference filters isolating the H{alpha}+[NII] emission lines to derive the amount and morphology of dust and ionized gas. To improve the wavelength coverage we retrieved data from the Sloan Digital Sky Survey and Two Micron All Sky Survey and combined these with our data. Ionized gas is detected in 25 galaxies and shows in most cases a smooth morphology, although knots and filamentary structure are also observed in some objects.
- ID:
- ivo://CDS.VizieR/J/A+A/590/A67
- Title:
- Ionized gas maps of local U/LIRGs
- Short Name:
- J/A+A/590/A67
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a 2D study of star formation at kpc and sub-kpc scales of a sample of local (z<0.1) U/LIRGs, based on near-IR VLT-SINFONI observations. We obtained integrated measurements of the star formation rate (SFR) and star formation rate surface density, together with their 2D distributions, based on Br_gamma and Pa_alpha emission. We observe a tight linear correlation between the SFR derived from our extinction-corrected measurements and that derived from 24 micron data, and a reasonable agreement with SFR derived from total IR luminosity. Our near-IR measurements are on average a factor 3 larger than optical SFR, even when extinction corrections are applied. We found that LIRGs have a median-observed star formation rate surface density of 1.72M_{sun}_/yr/kpc^2^ for the extinction-corrected distribution, whilst ULIRGs have 0.23M_{sun}_/yr/kpc^2, respectively. These median values for ULIRGs increase up to 2.90M_{sun}_/yr/kpc^2^, when only their inner regions, covering the same size as the average FoV of LIRGs, are considered. We identified a total of 95 individual SF clumps in our sample, with sizes within 60-1500pc, and extinction-corrected Pa_alpha luminosities of 10^5^-10^8^L_{sun}_. Star-forming clumps in LIRGs are about ten times larger and thousands of times more luminous than typical clumps in spiral galaxies. Clumps in ULIRGs have sizes similar (x0.5-1) to those of high-z clumps, having Pa_alpha luminosities similar to some high-z clumps, and about 10 times less luminous than the most luminous high-z clumps identified so far. We also observed a change in the slope of the L-r relation. A likely explanation is that most luminous galaxies are interacting and merging, and therefore their size represents a combination of the distribution of the star-forming clumps within each galaxy in the system plus the effect of the projected distance.
