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Determining accurate effective temperatures of stars buried in the dust-obscured Galactic regions is extremely difficult from photometry. Fortunately, high-resolution infrared spectroscopy is a powerful tool for determining the temperatures…

Diffuse interstellar bands (DIBs) hold a lot of information about the state and the structure of the ISM. Structure can most directly be observed by extensive spectroscopic surveys, including surveys of stars where DIBs are especially…

Astrophysics of Galaxies · Physics 2017-05-10 Janez Kos

We present a new method for probing the physical conditions and metal enrichment of the Intergalactic Medium: the composite spectrum of Ly-alpha forest absorbers. We apply this technique to a sample of 9480 Ly-alpha absorbers with redshift…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Matthew M. Pieri , Stephan Frank , David H. Weinberg , Smita Mathur , Donald G. York

Context. Absorption line indices are widely used to determine the stellar population parameters such as age and metallicity of galaxies, but it is not easy to obtain the line indices of some distant galaxies that have colours available.…

Astrophysics of Galaxies · Physics 2015-05-20 Zhongmu LI , Ruheng LI , Ruxi LI

High-dispersion time-resolved spectroscopy of the unique magnetic cataclysmic variable AE Aqr is presented. A radial velocity analysis of the absorption lines yields K_2 = 168.7+/- 1 km/s. Substantial deviations of the radial velocity curve…

Astrophysics · Physics 2009-11-13 J. Echevarria , R. Connon Smith , R. Costero , S. Zharikov , R. Michel

We report on the performance of the statistical, X-ray absorption lines identification procedure XLINE-ID. As illustration, it is used to estimate the time averaged gas density $n_H(r)$ of a representative AGN's warm absorber ($T\approx…

Astrophysics of Galaxies · Physics 2016-08-08 J. M. Ramirez-Velasquez , J. Garcia

We present moderate resolution (R > 1,800) infrared K-band spectra of twelve long-period (Porb > 6 hr) cataclysmic variables. We detect absorption lines from the photospheres of the secondary stars in every system, even though two of the m…

Astrophysics · Physics 2009-11-10 Thomas E. Harrison , Heather L. Osborne , Steve B. Howell

We present intermediate resolution (R ~ 8,000 - 12,000) high signal-to-noise H- and K-band spectroscopy of a sample of 37 optically visible stars, ranging in spectral type from O3 to B3 and representing most luminosity classes. Spectra of…

Astrophysics · Physics 2011-07-18 M. M. Hanson , R. -P. Kudritzki , M. A. Kenworthy , J. Puls , A. T. Tokunaga

We describe a technique for deriving effective temperatures, surface gravities, rotation velocities, and radial velocities from high resolution near-IR spectra. The technique matches the observed near-IR spectra to spectra synthesized from…

Astrophysics · Physics 2009-11-10 G. W. Doppmann , D. T. Jaffe

We have investigated the absorption shapes of atomic lines and H{\alpha} in RR Lyrae stars. We used the database of high resolution spectra gathered with the Las Campanas Observatory du Pont Telescope, analyzing a set of about 2700 short…

Solar and Stellar Astrophysics · Physics 2024-04-03 Christopher Sneden , George W. Preston

We present a catalog of J-band spectra for 88 fundamental MK standard stars observed at a resolving power of R ~ 3000. This contribution serves as a companion atlas to the K-band spectra published by Wallace and Hinkle (1997) and the H-band…

Astrophysics · Physics 2009-10-31 Lloyd Wallace , Michael R. Meyer , Kenneth Hinkle , Suzan Edwards

Millimetre-band scans of the frequency space towards optically dim quasars is potentially a highly efficient method for detecting new high redshift molecular absorption systems. Here we describe scans towards 7 quasars over wide bandwidths…

Astrophysics · Physics 2007-05-23 S. J. Curran , J. K. Webb , M. T. Murphy , N. Kuno

Spectra of the He I 10830 line have been obtained for 23 metal-poor stars, the majority of which are dwarfs ranging in metallicity from [Fe/H] = -2.1 to -0.8. The data were acquired with the NIRSPEC spectrograph on the Keck 2 telescope.…

Solar and Stellar Astrophysics · Physics 2015-06-15 Graeme H. Smith , Andrea K. Dupree , Jay Strader

(abridged) We develop a tool for the automated spectral classification of OB stars according to their sub-types. We use the regular Random Forest (RF) algorithm, the Probabilistic RF (PRF), and we introduce the KDE-RF method which is a…

Solar and Stellar Astrophysics · Physics 2022-01-12 E. Kyritsis , G. Maravelias , A. Zezas , P. Bonfini , K. Kovlakas , P. Reig

I present a GHRS archival study of the interstellar absorption lines in the line-of-sight to the HI-rich starburst dwarf galaxy NGC 1705, in the 1170 to 1740A range at ~ 120 km/s resolution. The absorption features arising due to…

Astrophysics · Physics 2009-10-30 M. S. Sahu

One of the main problems in modeling the ionised outflows in Active Galactic Nuclei is the unknown distance of the outflowing wind to the central source. Only if the density is known this distance can be determined through the ionisation…

We present near-infrared (1 to 2.5 micron) low-resolution spectroscopy of eleven ultracool dwarfs with spectral types ranging from M7 to L8. Combining our observations with data published previously by Leggett et al. (2001), we have…

Astrophysics · Physics 2010-01-07 I. Neill Reid , A. J. Burgasser , K. L. Cruz , J. Davy Kirkpatrick , J. E. Gizis

We examine the absorption line spectra of a sample of 31 luminous (M_UV=-23) Lyman break galaxies at redshift z~6 using data taken with the FOCAS and OSIRIS spectrographs on the Subaru and GTC telescopes. For two of these sources we present…

Astrophysics of Galaxies · Physics 2020-10-28 Yuichi Harikane , Nicolas Laporte , Richard S. Ellis , Yoshiki Matsuoka

We have obtained high resolution (R = 10,000) K-band spectra of candidate young massive stars deeply embedded in high-mass star-forming regions. These objects were selected from a near-infrared survey of 44 regions of high-mass…

Astrophysics · Physics 2007-05-23 A. Bik , L. Kaper , M. M. Hanson , L. B. F. M. Waters

Using the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST) the COS Science Team has conducted a high signal-to-noise survey of 14 bright QSOs. In a previous paper (Savage et al. 2014) these far-UV spectra were used to…