English
Related papers

Related papers: A Low-Mass H2 Component to the AU Microscopii Circ…

200 papers

We present a neutral hydrogen-selected absorption-line survey of gas with HI column densities 15<log N(HI)<19 at z<1 using the Cosmic Origins Spectrograph on the Hubble Space Telescope. Our main aim is to determine the metallicity…

Context - Circumstellar discs are ubiquitous around young stars, but rapidly dissipate their gas and dust on timescales of a few Myr. The Herschel space observatory allows for the study of the warm disc atmosphere, using far-infrared…

We present an analysis of archival ISO observations of pure-rotational lines of H2 in three pointings in the central 3 parsecs of the Galaxy: toward the Southwest region and Northeast region of the Galactic center Circumnuclear Disk, and…

Astrophysics of Galaxies · Physics 2017-12-13 E. A. C. Mills , A. Togi , M. Kaufman

We study the column densities of neutral atomic, molecular, and warm ionized Galactic gas through their continuous absorption of extragalactic X-ray spectra at |b| > 25 degrees. For N(H,21cm) < 5x10^20 cm^-2 there is an extremely tight…

Astrophysics · Physics 2014-10-13 John S. Arabadjis , Joel N. Bregman

We present a Spitzer InfraRed Spectrometer search for 10-36 micron molecular emission from a large sample of protoplanetary disks, including lines from H2O, OH, C2H2, HCN and CO2. This paper describes the sample and data processing and…

Earth and Planetary Astrophysics · Physics 2015-05-19 Klaus M. Pontoppidan , Colette Salyk , Geoffrey A. Blake , Rowin Meijerink , John S. Carr , Joan Najita

We report new Atacama Large Millimeter/Submillimeter Array (ALMA) observations of a circumstellar disk around Source I in Orion KL, an archetype of massive protostar candidate. We detected two ortho-H$_{2}$O lines at 321 GHz…

Solar and Stellar Astrophysics · Physics 2015-06-18 Tomoya Hirota , Mi Kyoung Kim , Yasutaka Kurono , Mareki Honma

We present a comparison of archival Spitzer spectra of the strongly variable T Tauri EX Lupi, observed before and during its 2008 outburst. We analyze the mid-infrared emission from gas-phase molecules thought to originate in a…

Earth and Planetary Astrophysics · Physics 2015-06-03 A. Banzatti , M. R. Meyer , S. Bruderer , V. Geers , I. Pascucci , F. Lahuis , A. Juhasz , T. Henning , P. Abraham

We report the results of a search for pure rotational molecular hydrogen emission from the circumstellar environments of young stellar objects with disks using the Texas Echelon Cross Echelle Spectrograph (TEXES) on the NASA Infrared…

We present an analysis of Spitzer-IRS observations of H2O, OH, HCN, C2H2, and CO2 emission, and Keck-NIRSPEC observations of CO emission, from a diverse sample of T Tauri and Herbig Ae/Be circumstellar disks. We find that detections and…

Astrophysics of Galaxies · Physics 2015-03-19 C. Salyk , K. M. Pontoppidan , G. A. Blake , J. R. Najita , J. S. Carr

Context: Quantifying the gas content inside the dust gaps of transition disks is important to establish their origin. Aims: We seek to constrain the surface density of warm gas in the disk of HD 139614, a Herbig Ae star with a transition…

To probe the distribution and physical characteristics of interstellar gas at temperatures T ~ 3e5 K in the disk of the Milky Way, we have used the Far Ultraviolet Spectroscopic Explorer (FUSE) to observe absorption lines of OVI toward 148…

Aims. We model a diffuse molecular cloud present along the line of sight to the star HD 102065. We compare our modeling with observations to test our understanding of physical conditions and chemistry in diffuse molecular clouds. Methods.…

We present detailed model fits to observations of the disc around the Herbig Ae star HD 163296. This well-studied object has an age of ~ 4 Myr, with evidence of a circumstellar disc extending out to ~ 540AU. We use the radiation…

The total disk mass sets the formation potential for exoplanets. Carbon-monoxide (CO) has been used as a gas mass tracer in T Tauri disks, but was found to be less abundant than expected due to freeze-out and chemical conversion of CO on…

Earth and Planetary Astrophysics · Physics 2023-12-08 L. M. Stapper , M. R. Hogerheijde , E. F. van Dishoeck , L. Lin , A. Ahmadi , A. S. Booth , S. L. Grant , K. Immer , M. Leemker , A. F. Pérez-Sánchez

We present the first detection of 12 CO J=2->1 and 12 CO J=1->0 emission from the LBV AG Carinae. AG Carinae resides in a region which is very rich in molecular gas with complex motions. We find evidence of a slow outflow of molecular gas,…

Spectra of about 150 early-type stars in the disk of the Milky Way recorded by the Far Ultraviolet Spectroscopic Explorer (FUSE) reveal absorption features from interstellar O VI, a tracer of collisionally ionized gases at temperatures near…

We present a study of the abundances and physical conditions in the interstellar gas toward the heavily reddened star HD 192639 [E_(B-V) = 0.64], based on analysis of FUSE and HST/STIS spectra covering the range from 912 to 1361 A. This…

Astrophysics · Physics 2009-11-07 P. Sonnentrucker , S. D. Friedman , D. E. Welty , D. G. York , T. P. Snow

We aim to explore the capabilities of dust emission and rays for probing the properties of the interstellar medium in the nearby anti-centre region, using gamma-ray observations with the Fermi Large Area Telescope (LAT), and the thermal…

High Energy Astrophysical Phenomena · Physics 2017-05-10 Q. Remy , I. A. Grenier , D. J. Marshall , J. M. Casandjian

We detect emission from multiple low-excitation ro-vibrational transitions of OH from the two Herbig Ae stars AB Aurigae and MWC 758 in the 3.0 - 3.7 micron wavelength range (L-band), using the NIRSPEC instrument on Keck II. The inner…

The pumping of 22.2-GHz H$_2$O masers in the circumstellar envelopes of asymptotic giant branch stars has been simulated numerically. The physical parameters adopted in the calculations correspond to those of the circumstellar envelope…

Astrophysics of Galaxies · Physics 2013-10-01 Aleksandr Nesterenok