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1591. Spectra of blue compact galaxies
ID:
ivo://CDS.VizieR/J/A+A/396/503
Title:
Spectra of blue compact galaxies
Short Name:
J/A+A/396/503
Date:
21 Oct 2021
Publisher:
CDS
Description:
This is the second paper in a series studying the star formation rates, stellar components, metallicities, and star formation histories and evolution of a sample of blue compact galaxies. We analyzed spectral properties of 97 blue compact galaxies, obtained with the Beijing Astronomical Observatory (China) 2.16m telescope, with spectral range 3580{AA}-7400{AA}. We classify the spectra according to their emission lines: 13 of the total 97 BCG sample are non-emission line galaxies (non-ELGs); 10 have AGN-like emission (AGNs), and 74 of them are star-forming galaxies (SFGs). Emission line fluxes and equivalent widths, continuum fluxes, the 4000A Balmer break index and equivalent widths of absorption lines are measured from the spectra. Please find more detail information in http://optik2.mtk.nao.ac.jp/~xkong/bcg/
1592. Spectra of blue compact galaxies
ID:
ivo://CDS.VizieR/J/A+A/389/845
Title:
Spectra of blue compact galaxies
Short Name:
J/A+A/389/845
Date:
21 Oct 2021
Publisher:
CDS
Description:
Blue compact galaxies are compact objects that are dominated by intense star formation. Most of them have dramatically different properties compared to the Milky Way and many other nearby galaxies. Using the IRAS, HI data, and optical spectra, we wanted to measure the current star formation rates, stellar components, metallicities, and star formation histories and evolution of a large blue compact galaxy sample. We anticipate that our study will be useful as a benchmark for studies of emission line galaxies at high redshift. In the first paper of this series, we describe the selection, spectroscopic observation, data reduction and calibration, and spectrophotometric accuracy of a sample of 97 luminous blue compact galaxies. We present a spectrophotometric atlas of rest-frame spectra, as well as tables of the recession velocities and the signal-to-noise ratios. The recession velocities of these galaxies are measured with an accuracy of {delta}V<67km/s. The average signal-to-noise ratio of sample spectra is ~51. The spectral line strengths, equivalent widths and continuum fluxes are also measured for the same galaxies and will be analyzed in the next paper of this series.
1593. Spectra of candidate standard stars in mid-IR
ID:
ivo://CDS.VizieR/J/AJ/149/11
Title:
Spectra of candidate standard stars in mid-IR
Short Name:
J/AJ/149/11
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present spectra obtained with the Infrared Spectrograph (IRS) on the Spitzer Space Telescope of 33 K giants and 20 A dwarfs to assess their suitability as spectrophotometric standard stars. The K giants confirm previous findings that the strength of the SiO absorption band at 8{mu}m increases for both later optical spectral classes and redder (B-V)_0_ colors, but with considerable scatter. For K giants, the synthetic spectra underpredict the strengths of the molecular bands from SiO and OH. For these reasons, the assumed true spectra for K giants should be based on neither the assumption that molecular band strengths in the infrared can be predicted accurately from optical spectral class or color nor synthetric spectra. The OH bands in K giants grow stronger with cooler stellar temperatures, and they are stronger than predicted by synthetic spectra. As a group, A dwarfs are better behaved and more predictable than the K giants, but they are more likely to show red excesses from debris disks. No suitable A dwarfs were located in parts of the sky continuously observable from Spitzer, and with previous means of estimating the true spectra of K giants ruled out, it was necessary to use models of A dwarfs to calibrate spectra of K giants from observed spectral ratios of the two groups and then use the calibrated K giants as standards for the full database of infrared spectra from Spitzer. We also describe a lingering artifact that affects the spectra of faint blue sources at 24{mu}m.
1594. Spectra of CO and [CI] in protoplanetary disks
ID:
ivo://CDS.VizieR/J/A+A/588/A108
Title:
Spectra of CO and [CI] in protoplanetary disks
Short Name:
J/A+A/588/A108
Date:
21 Oct 2021
Publisher:
CDS
Description:
The gas-solid budget of carbon in protoplanetary disks is related to the composition of the cores and atmospheres of the planets forming in them. The principal gas-phase carbon carriers CO, C^0^, and C^+6 can now be observed regularly in disks. The gas-phase carbon abundance in disks has thus far not been well characterized observationally. We obtain new constraints on the [C]/[H] ratio in a large sample of disks, and compile an overview of the strength of [CI] and warm CO emission. We carried out a survey of the CO 6-5 line and the [CI] 1-0 and 2-1 lines towards 37 disks with the APEX telescope, and supplemented it with [CII] data from the literature. The data are interpreted using a grid of models produced with the DALI disk code. We also investigate how well the gas-phase carbon abundance can be determined in light of parameter uncertainties.
1595. Spectra of Earth-like planets around M-dwarfs
ID:
ivo://CDS.VizieR/J/A+A/624/A49
Title:
Spectra of Earth-like planets around M-dwarfs
Short Name:
J/A+A/624/A49
Date:
21 Oct 2021
Publisher:
CDS
Description:
The characterisation of the atmosphere of exoplanets is one of the main goals of exoplanet science in the coming decades. We investigate the detectability of atmospheric spectral features of Earth-like planets in the habitable zone (HZ) around M dwarfs with the future James Webb Space Telescope (JWST). We used a coupled 1D climate-chemistry-model to simulate the influence of a range of observed and modelled M-dwarf spectra on Earth-like planets. The simulated atmospheres served as input for the calculation of the transmission spectra of the hypothetical planets, using a line-by-line spectral radiative transfer model. To investigate the spectroscopic detectability of absorption bands with JWST we further developed a signal- to-noise ratio (S/N) model and applied it to our transmission spectra. High abundances of methane (CH_4_) and water (H_2_O) in the atmosphere of Earth-like planets around mid to late M dwarfs increase the detectability of the corresponding spectral features compared to early M-dwarf planets. Increased temperatures in the middle atmosphere of mid- to late-type M-dwarf planets expand the atmosphere and further increase the detectability of absorption bands. To detect CH_4_, H_2_O, and carbon dioxide (CO_2_) in the atmosphere of an Earth-like planet around a mid to late M dwarf observing only one transit with JWST could be enough up to a distance of 4pc and less than ten transits up to a distance of 10pc. As a consequence of saturation limits of JWST and less pronounced absorption bands, the detection of spectral features of hypothetical Earth-like planets around most early M dwarfs would require more than ten transits. We identify 276 existing M dwarfs (including GJ 1132, TRAPPIST-1, GJ 1214, and LHS 1140) around which atmospheric absorption features of hypothetical Earth-like planets could be detected by co-adding just a few transits. The TESS satellite will likely find new transiting terrestrial planets within 15pc from the Earth. We show that using transmission spectroscopy, JWST could provide enough precision to be able to partly characterise the atmosphere of TESS findings with an Earth-like composition around mid to late M dwarfs.
1596. Spectra of 2 halo red horizontal branch stars
ID:
ivo://CDS.VizieR/J/A+A/559/A12
Title:
Spectra of 2 halo red horizontal branch stars
Short Name:
J/A+A/559/A12
Date:
21 Oct 2021
Publisher:
CDS
Description:
High-velocity halo stars provide important information about the properties of the extreme Galactic halo. The study of Population II unbound and bound stars enables us better estimate the mass of the halo. We carried out a detailed spectroscopic and kinematic study of two red horizontal branch stars, CD-41 5048 and HD 214362.
1597. Spectra of 7 H{alpha} emission line stars in MBM 18
ID:
ivo://CDS.VizieR/J/A+A/547/A85
Title:
Spectra of 7 H{alpha} emission line stars in MBM 18
Short Name:
J/A+A/547/A85
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate star formation in translucent, high-latitude clouds. Our aim is to understand the star-formation history and rate in the solar neighbourhood. We used spectroscopic observations of newly found candidate H{alpha} emission-line stars to establish their pre-main-sequence nature. The environment was studied through molecular line observations of the cloud (MBM 18/LDN 1569) in which the stars are presumably embedded.
1598. Spectra of high-mass X-ray binaries
ID:
ivo://CDS.VizieR/J/A+A/590/A122
Title:
Spectra of high-mass X-ray binaries
Short Name:
J/A+A/590/A122
Date:
21 Oct 2021
Publisher:
CDS
Description:
High-mass X-ray binaries are bright X-ray sources. The high-energy emission is caused by the accretion of matter from the massive companion onto a neutron star. The accreting material comes from either the strong stellar wind in binaries with supergiant companions or the circumstellar disk in Be/X-ray binaries. In either case, the H{alpha} line stands out as the main source of information about the state of the accreting material. We present the results of our monitoring program to study the long-term variability of the H{alpha} line in high-mass X-ray binaries. Our aim is to characterise the optical variability timescales and study the interaction between the neutron star and the accreting material. We fitted the H{alpha} line with Gaussian profiles and obtained the line parameters and equivalent width. The peak separation in split profiles was used to determine the disk velocity law and estimate the disk radius. The relative intensity of the two peaks (V/R ratio) allowed us to investigate the distribution of gas particles in the disk. The equivalent width was used to characterise the degree of variability of the systems. We also studied the variability of the H{alpha} line in correlation with the X-ray activity.
1599. Spectra of IPHAS symbiotic stars
ID:
ivo://CDS.VizieR/J/A+A/567/A49
Title:
Spectra of IPHAS symbiotic stars
Short Name:
J/A+A/567/A49
Date:
21 Oct 2021
Publisher:
CDS
Description:
The IPHAS H{alpha} survey provides a rich database to search for emission-line sources in the northern Galactic plane. We are systematically searching for symbiotic stars in the Milky Way using IPHAS. Our final goal, a complete census of this class of objects in the Galaxy, is a fundamental figure for discussing their overall properties and relevance to other classes of stars. Candidate symbiotic stars were selected using a refined combination of IPHAS and 2MASS photometric colours. Optical spectroscopy, together with the analysis of their spectral energy distribution in the IR, were obtained to confirm their nature and determine their main properties.
1600. Spectra of Late-Type Standards, 2.0-2.5 Microns
ID:
ivo://CDS.VizieR/III/114
Title:
Spectra of Late-Type Standards, 2.0-2.5 Microns
Short Name:
III/114
Date:
21 Oct 2021
Publisher:
CDS
Description:
This catalog contains a collection of K-band spectra for 26 stars with near-solar abundances, ranging in spectral class from F8 to M7 and in luminosity from dwarfs to supergiants. The spectra cover the wavelength region from 4150 to 4950 /cm and generally exhibit a signal to noise ratio above 400. Five stars here are supergiants, 15 are giants, and six are dwarfs. Data included: observation date, starting wavenumber, wavenumber increment, scale factor of relative intensity, and offset of relative intensity.