Results 81 to 90 of about 1,217 (186)

FAST Search for Circumstellar Atomic Hydrogen. III. Planetary Nebulae at Galactic Latitudes ∣b∣ ≥ 10°

The Astronomical Journal
The detection of circumstellar atomic hydrogen (H i ) via the 21 cm line remains a persistent challenge in planetary nebula (PN) studies, primarily due to contamination from ubiquitous interstellar H i 21 cm emission. In this paper, we report the results
Xu-Jia Ouyang, Yong Zhang, Albert Zijlstra, Chuan-Peng Zhang, Jun-ichi Nakashima, Quentin A. Parker, Xiao-Hu Li   +6 more
doaj   +1 more source

A Simulated Galaxy Laboratory: Exploring the Observational Effects on UV Spectral Absorption Line Measurements

The Astrophysical Journal
Ultraviolet absorption line spectroscopy is a sensitive diagnostic for the properties of interstellar and circumgalactic gas. Down-the-barrel observations, where the absorption is measured against the galaxy itself, are commonly used to study feedback ...
R. Michael Jennings, Alaina Henry, Valentin Mauerhofer, Timothy Heckman, Claudia Scarlata, Cody Carr, Xinfeng Xu, Mason Huberty, Simon Gazagnes, Anne E. Jaskot, Jeremy Blaizot, Anne Verhamme, Sophia R. Flury, Alberto Saldana-Lopez, Matthew J. Hayes, Maxime Trebitsch   +15 more
doaj   +1 more source

Quasar Winds Caught on Acceleration and Deceleration

The Astrophysical Journal Supplement Series
We present an observational study of wind acceleration based on four low-ionization broad absorption line (BAL) quasars (J0136, J1238, J1259, and J1344).
Weimin Yi, P. B. Hall, Zunli Yuan, W. N. Brandt, D. P. Schneider, Zhicheng He, Jin-Ming Bai, Xue-Bing Wu   +7 more
doaj   +1 more source

A Catalog of Hα Emission-line Stars and 785 Newly Identified Young Stellar Object Candidates from LAMOST Based on a Deep Learning Method

The Astrophysical Journal Supplement Series
The H α emission line commonly appears in the spectra of many stars and serves as a key indicator for tracing ionized interstellar gas, investigating stellar activity, and studying gas dynamics.
Lei Tan, Ying Mei, Jiale Qian, Xiaolong Wang, Yue Cui, Aixin Huang, Feng Wang, Hui Deng, Chao Liu, Huanbin Chi   +9 more
doaj   +1 more source

Unusual X-Ray Oxygen Line Ratios of SN 1987A Arising from the Absorption of Galactic Hot Interstellar Medium

The Astrophysical Journal
Recent high-resolution X-ray spectroscopic studies have revealed unusual oxygen line ratios, such as the high O vii forbidden-to-resonance ratio, in several supernova remnants. While the physical origin is still under debate, for most of them it has been
Lei Sun, Salvatore Orlando, Emanuele Greco, Marco Miceli, Yiping Li, Yang Chen, Jacco Vink, Ping Zhou   +7 more
doaj   +1 more source

High-resolution Mid-infrared Spectroscopy of SVS13-A with EXES/SOFIA: The Surprisingly High CH3OH/H2O Ratio in the Planet-forming Zone of a Solar Mass Protostar

The Astrophysical Journal Letters
Water and methanol are key components of interstellar ices and gas in star- and planet-forming regions, but direct observations of water in low-mass protostars are challenging due to atmospheric absorption.
Curtis DeWitt, Marta De Simone, Eleonora Bianchi, Cecilia Ceccarelli, Claudio Codella, Sarah Nickerson, Keeyoon Sung, Albert Rimola, Vittorio Bariosco, Piero Uliengo, Naseem Rangwala   +10 more
doaj   +1 more source

XP-TEAL: Gaia XP tool for emission and absorption lines

Astronomy & Astrophysics
Context. The third Gaia data release (Gaia DR3) includes blue and red low-resolution spectrophotometry for more than 200 million sources. These Gaia XP spectra are represented by sets of coefficients multiplying linear combinations of basis functions ...
Carrasco J. M., Weiler M., Malhotra S., Anders F., Jordi C., Masana E., Castañeda J., Boix F.   +7 more
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Absorption Lines Produced in Interstellar Grains.

The Astronomical Journal, 1963
J. Mayo Greenberg, Pearl R. Lichtenstein
openaire   +1 more source

Elemental Abundances in the Diffuse Interstellar Medium from Joint Far-ultraviolet and X-Ray Spectroscopy: Iron, Oxygen, Carbon, and Sulfur

The Astronomical Journal
In this study, we investigate interstellar absorption lines along the line of sight toward the galactic low-mass X-ray binary Cygnus X-2. We combine absorption line data obtained from high-resolution X-ray spectra collected with the Chandra and XMM ...
I. Psaradaki, L. Corrales, J. Werk, A. G. Jensen, E. Costantini, M. Mehdipour, R. Cilley, N. Schulz, J. Kaastra, J. A. García, L. Valencic, T. Kallman, F. Paerels   +12 more
doaj   +1 more source

Photocleavage of Aliphatic C–C Bonds in the Interstellar Medium

The Astrophysical Journal
Ultraviolet (UV) processing in the interstellar medium (ISM) induces the dehydrogenation of hydrocarbons. Aliphatics, including alkanes, are present in different interstellar environments, being prevalently formed in evolved stars; thus, the ...
Guillermo Tajuelo-Castilla, Jesús I. Mendieta-Moreno, Mario Accolla, Jesús M. Sobrado, Sofia Canola, Pavel Jelínek, Gary J. Ellis, José Ángel Martín-Gago, Gonzalo Santoro   +8 more
doaj   +1 more source