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1271. IUE Low-Dispersion Reference Atlas I, Normal Stars
ID:
ivo://CDS.VizieR/III/83
Title:
IUE Low-Dispersion Reference Atlas I, Normal Stars
Short Name:
III/83
Date:
21 Oct 2021
Publisher:
CDS
Description:
The atlas contains the fluxes (2 angstroms/step) of 229 low-dispersion stellar spectra collected by the International Ultraviolet Explorer (IUE) satellite, compiled for the purpose of establishing reference spectral sequences in the ultraviolet range. The sequences have been constructed and the standard stars selected directly from the ultraviolet material, staying as far as possible within the general MK frame. The catalog is essentially composed of stars exhibiting normal behaviour in the ultraviolet. A few peculiar objects have, however, been included as an illustration of typical abnormalities. This work clearly pointed out the dangers of extrapolating a spectral classification based on a given wavelength range to another one, and, in particular, of using the MK spectral type alone outside its definition range.
1272. IUE low-dispersion spectra of white dwarfs
ID:
ivo://CDS.VizieR/J/ApJS/147/145
Title:
IUE low-dispersion spectra of white dwarfs
Short Name:
J/ApJS/147/145
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have produced an archive of the ultraviolet low-dispersion spectra for the full set of white dwarf stars observed with the International Ultraviolet Explorer (IUE) satellite over the course of its 18-yr mission. This archive contains the spectra of 322 individual degenerate stars which have been processed to optimize the signal-to- noise for each star. In particular, all spectra have been corrected for residual temporal and thermal effects and placed on the Hubble Space Telescope Faint Object Spectrograph absolute flux scale using procedures described by Massa & Fitzpatrick (2000ApJS..126..517M). Wherever possible, multiple observations of individual stars have been co-added to further enhance signal-to-noise and have been combined into a single spectrum including the full 1150 to 3150{AA} wavelength region observed by IUE. The contents of this spectral archive are described and the details of data reduction procedures are provided. The electronic files of the processed spectra are available, in FITS and ASCII formats, with the associated log file, at http://vega.lpl.arizona.edu/newsips/low/
1273. IUE sample of binaries with hot component
ID:
ivo://CDS.VizieR/J/ApJS/119/83
Title:
IUE sample of binaries with hot component
Short Name:
J/ApJS/119/83
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have obtained or retrieved IUE spectra for over 100 middle- and late-type giant and supergiant stars whose spectra indicate the presence of a hot component earlier than type F2. The hot companions are classified accurately by temperature class from their far-UV spectra. The interstellar extinction of each system and the relative luminosities of the components are derived from analysis of the UV and optical fluxes, using a grid of UV intrinsic colors for hot dwarfs. We find that there is fair agreement in general between current UV spectral classification and ground-based hot component types, in spite of the difficulties of assigning the latter. There are a few cases in which the cool component optical classifications disagree considerably with the temperature classes inferred from our analysis of UV and optical photometry. The extinction parameter agrees moderately well with other determinations of B-V color excess. Many systems are worthy of further study especially to establish their spectroscopic orbits. Further work is planned to estimate luminosities of the cool components from the data herein; in many cases, these luminosities' accuracies should be comparable to or exceed those of the Hipparcos parallaxes.
1274. IUE spectra of lambda Boo stars
ID:
ivo://CDS.VizieR/J/A+A/331/633
Title:
IUE spectra of lambda Boo stars
Short Name:
J/A+A/331/633
Date:
21 Oct 2021
Publisher:
CDS
Description:
An analysis of the stars included in the catalogue of {lambda} Bootis stars by Paunzen et al. (1997, Cat. <J/A+AS/123/93>) and which also have IUE observations is presented here. Population I A-F type stars as well as field horizontal branch stars were also included in the analysis. Using line-ratios of carbon to heavier elements (Al and Ni) allows us to establish unambiguous membership criteria for the {lambda} Bootis group.
1275. IUE spectra of WR stars
ID:
ivo://CDS.VizieR/J/A+AS/108/669
Title:
IUE spectra of WR stars
Short Name:
J/A+AS/108/669
Date:
21 Oct 2021
Publisher:
CDS
Description:
(no description available)
1276. I Zw 1 unusual emission line spectrum
ID:
ivo://CDS.VizieR/J/A+A/417/515
Title:
I Zw 1 unusual emission line spectrum
Short Name:
J/A+A/417/515
Date:
08 Mar 2022
Publisher:
CDS
Description:
Most Seyfert 1s show strong FeII lines in their spectrum having the velocity and width of the broad emission lines. To remove the FeII contribution in these objects, an accurate template is necessary. We used very high signal-to-noise, medium resolution archive optical spectra of I Zw 1 to build such a template. I Zw 1 is a bright narrow-line Seyfert 1 galaxy. As such it is well suited for a detailed analysis of its emission line spectrum. Furthermore it is known to have a very peculiar spectrum with, in addition to the usual broad and narrow line regions, two emission regions emitting broad and blue shifted [OIII] lines making it a peculiarly interesting object. While analysing the spectra, we found that the narrow-line region is, unlike the NLR of most Seyfert 1 galaxies, a very low excitation region dominated by both permitted and forbidden FeII lines. It is very similar to the emission spectrum of a blob in {eta} Carinae which is a low temperature (T~6500K), relatively high density (N_e_=10^6^cm^-3) cloud. The FeII lines in this cloud are mainly due to pumping via the stellar continuum radiation field (Verner et al., 2002ApJ...581.1154V). We did not succeed in modelling the spectrum of the broad-line region, and we suggest that a non radiative heating mechanism increases the temperature in the excited HI region, thus providing the necessary additional excitation of the FeII lines. For the low-excitation narrow-line region, we are able to settle boundaries to the physical conditions accounting for the forbidden and permitted FeII lines (10^6^<N_e_<10^7^cm^-3^; 10^-6^<U<10^-5^).
1277. J1717-3342 and J1744-3116 CO spectra
ID:
ivo://CDS.VizieR/J/A+A/648/A38
Title:
J1717-3342 and J1744-3116 CO spectra
Short Name:
J/A+A/648/A38
Date:
21 Oct 2021
Publisher:
CDS
Description:
The chemistry of the diffuse interstellar medium is driven by the combined influences of cosmic rays, ultraviolet (UV) radiation, and turbulence. Previously detected at the outer edges of photodissociation regions (PDRs) and formed from the reaction of C^+^ and OH, CO^+^ is the main chemical precursor of HCO^+^ and CO in a thermal, cosmic-ray, and UV-driven chemistry. Our aim was to test whether the thermal cosmic-ray and UV-driven chemistry is producing CO in diffuse interstellar molecular gas through the intermediate formation of CO^+^ We searched for CO^+^ absorption with the Atacama Large Millimeter Array (ALMA) toward two quasars with known Galactic foreground absorption from diffuse interstellar gas, J1717-3342 and J1744-3116, targeting the two strongest hyperfine components of the J=2-1 transition near 236GHz. We could not detect CO^+^ but obtained sensitive upper limits toward both targets. The derived upper limits on the CO^+^ column densities represent about 4% of the HCO^+^ column densities. The corresponding upper limit on the CO^+^ abundance relative to H_2_ is <1.2x10^-10^. The non-detection of CO^+^ confirms that HCO^+^ is mainly produced in the reaction between oxygen and carbon hydrides, CH2^+^ or CH3^+^, induced by suprathermal processes, while CO^+^ and HOC^+^ result from reactions of C^+^ with OH and H_2_O. The densities r equired to form CO molecules at low extinction are consistent with this scheme.
1278. Jekyll & Hyde galaxies ALMA cube & spectrum
ID:
ivo://CDS.VizieR/J/A+A/611/A22
Title:
Jekyll & Hyde galaxies ALMA cube & spectrum
Short Name:
J/A+A/611/A22
Date:
21 Oct 2021
Publisher:
CDS
Description:
We obtained ALMA spectroscopy and deep imaging to investigate the origin of the unexpected sub-millimeter emission toward the most distant quiescent galaxy known to date, ZF-COSMOS-20115 at z=3.717. We show here that this sub-millimeter emission is produced by another massive (M*~10^11^M_{sun}_), compact (r_1/2_=0.67+/-0.14kpc) and extremely obscured galaxy (A_V_~3.5), located only 0.4300 (3.1kpc) away from the quiescent galaxy. We dub the quiescent and dusty galaxies Jekyll and Hyde, respectively. No dust emission is detected at the location of the quiescent galaxy, implying SFR<13M_{sun}_/yr which is the most stringent upper limit ever obtained for a quiescent galaxy at these redshifts. The two sources are spectroscopically confirmed to lie at the same redshift thanks to the detection of [CII]158 in Hyde (z=3.709), which provides one the few robust redshifts for a highly-obscured "H-dropout" galax (H-[4.5]=5.1+/-0.8). The [CII] line shows a clear rotating-disk velocity profile which is blueshifted compared to the Balmer lines of Jekyll by 549+/-60km/s, demonstrating that it is produced by another galaxy. Careful de-blending of the Spitzer imaging confirms the existence of this new massive galaxy, and its non-detection in the Hubble images requires extremely red colors and strong attenuation by dust. Full modeling of the UV-to-far-IR emission of both galaxies shows that Jekyll has fully quenched at least 200Myr prior to observation and still presents a challenge for models, while Hyde only harbors moderate star-formation with SFR<~120M_{sun}/yr, and is located at least a factor 1.4 below the z~4 main sequence. Hyde could also have stopped forming stars less than 200Myr before being observed; this interpretation is also suggested by its compactness comparable to that of z~4 quiescent galaxies and its low [CII]/FIR ratio, but significant on-going star-formation cannot be ruled out. Lastly, we find that despite its moderate SFR, Hyde hosts a dense reservoir of gas comparable to that of the most extreme starbursts. This suggests that whatever mechanism has stopped or reduced its star-formation must have done so without expelling the gas outside of the galaxy. Because of their surprisingly similar mass, compactness, environment and star-formation history, we argue that Jekyll and Hyde can be seen as two stages of the same quenching process, and provide a unique laboratory to study this poorly understood phenomenon.
1279. JHK photometry and spectroscopy for L and T dwarfs
ID:
ivo://CDS.VizieR/J/AJ/127/3553
Title:
JHK photometry and spectroscopy for L and T dwarfs
Short Name:
J/AJ/127/3553
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present new JHK photometry on the MKO-NIR (Mauna Kea Observatories Near-Infrared) system and JHK spectroscopy for a large sample of L and T dwarfs. Photometry has been obtained for 71 dwarfs, and spectroscopy for 56. The sample comprises newly identified very red objects from the Sloan Digital Sky Survey (SDSS, http://www.sdss.org/) and known dwarfs from the SDSS and the Two Micron All Sky Survey (2MASS, Cat. <II/246>). Spectral classification has been carried out using four previously defined indices from Geballe et al. (2002ApJ...564..466G) that measure the strengths of the near infrared water and methane bands.
1280. J,H,K spectroscopy of HD 106906 b
ID:
ivo://CDS.VizieR/J/A+A/608/A71
Title:
J,H,K spectroscopy of HD 106906 b
Short Name:
J/A+A/608/A71
Date:
21 Oct 2021
Publisher:
CDS
Description:
Directly imaged planets are ideal candidates for spectroscopic characterization of their atmospheres. The angular separations that are typically close to their host stars, however, reduce the achievable contrast and thus signal-to-noise ratios (S/N). We spectroscopically characterize the atmosphere of HD 106906 b, which is a young low-mass companion near the deuterium burning limit. The wide separation from its host star of 7.1" makes it an ideal candidate for high S/N and high-resolution spectroscopy. We aim to derive new constraints on the spectral type, effective temperature, and luminosity of HD 106906 b and also to provide a high S/N template spectrum for future characterization of extrasolar planets. We obtained 1.1-2.5um integral field spectroscopy with the VLT/SINFONI instrument with a spectral resolution of R~=2000-4000. New estimates of the parameters of HD 106906 b are derived by analyzing spectral features, comparing the extracted spectra to spectral catalogs of other low-mass objects, and fitting with theoretical isochrones.

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