Zobrazeno 1 - 10
of 50
pro vyhledávání: '"Arshia, M."'
Autor:
Jacob, Arshia M., Nandakumar, Meera, Roy, Nirupam, Menten, Karl M., Neufeld, David A., Faure, Alexandre, Tiwari, Maitraiyee, Pillai, Thushara G. S., Robishaw, Timothy, Duran, Carlos A.
Publikováno v:
A&A 692, A164 (2024)
Ever since they were first detected in the interstellar medium, the radio wavelength (3.3 GHz) hyperfine-structure splitting transitions in the rotational ground state of CH have been observed to show anomalous excitation. Astonishingly, this behavio
Externí odkaz:
http://arxiv.org/abs/2411.08193
Publikováno v:
A&A 687, A29 (2024)
CF$^{+}$ has been established as a valuable diagnostic tool for investigating photo-dissociation regions (PDRs) and fluorine abundances in the Milky Way. However, its role in extragalactic environments remains largely uncharted. Our objective is to e
Externí odkaz:
http://arxiv.org/abs/2405.04719
Publikováno v:
A&A 675, A69 (2023)
While the abundance of elemental deuterium is relatively low (D/H ~ a few 1E-5), orders of magnitude higher D/H abundance ratios have been found for many interstellar molecules, enhanced by deuterium fractionation. In cold molecular clouds (T < 20K)
Externí odkaz:
http://arxiv.org/abs/2305.07143
Autor:
Jacob, Arshia M., Menten, Karl M., Wyrowski, Friedrich, Winkel, Benjamin, Neufeld, David A., Koribalski, Baerbel S.
Publikováno v:
A&A 659, A152 (2022)
Along several sight lines within the Milky Way ArH+ has been ubiquitously detected with only one detection in extragalactic environments, namely along two sight lines in the red shift z=0.89 absorber towards the lensed blazar PKS 1830-211. Being form
Externí odkaz:
http://arxiv.org/abs/2112.15546
Publikováno v:
A&A 650, A133 (2021)
The intensities of the three widely observed radio-wavelength hyperfine structure (HFS) lines between the {\Lambda}-doublet components of the rotational ground state of CH are inconsistent with LTE and indicate ubiquitous population inversion. While
Externí odkaz:
http://arxiv.org/abs/2104.04259
Autor:
Koley, Atanu, Roy, Nirupam, Menten, Karl M., Jacob, Arshia M., Pillai, Thushara G. S., Rugel, Michael R.
Measuring interstellar magnetic fields is extremely important for understanding their role in different evolutionary stages of interstellar clouds and of star formation. However, detecting the weak field is observationally challenging. We present mea
Externí odkaz:
http://arxiv.org/abs/2012.08253
Publikováno v:
A&A 643, A91 (2020)
One of the surprises of the Herschel mission was the detection of ArH+ towards the Crab Nebula in emission and in absorption towards strong Galactic background sources. Although these detections were limited to the first quadrant of the Galaxy, the e
Externí odkaz:
http://arxiv.org/abs/2010.02258
Autor:
Jacob, Arshia M., Menten, Karl M., Wiesemeyer, Helmut, Guesten, Rolf, Wyrowski, Friedrich, Klein, Bernd
Publikováno v:
A&A 640, A125 (2020)
In recent years, a plethora of high spectral resolution observations of sub-mm and FIR transitions of methylidene (CH), have demonstrated this radical to be a valuable proxy for H2, that can be used for characterising molecular gas within the interst
Externí odkaz:
http://arxiv.org/abs/2007.01190
Autor:
Jacob, Arshia M., Menten, Karl M., Wiesemeyer, Helmut, Lee, Min-Young, Güsten, Rolf, Durán, Carlos A.
Publikováno v:
A&A 632, A60 (2019)
In this paper, we investigate the influence of hyperfine splitting on complex spectral lines, with the aim of evaluating canonical abundances by decomposing their dependence on hyperfine structures. This is achieved from first principles through deco
Externí odkaz:
http://arxiv.org/abs/1911.00393
Autor:
Wiesemeyer, Helmut, Güsten, Rolf, Menten, Karl M., Durán, Carlos A., Csengeri, Timea, Jacob, Arshia M., Simon, Robert, Stutzki, Jürgen, Wyrowski, Friedrich
The methylidyne radical CH is commonly used as a proxy for H$_2$ in the cold, neutral phase of the interstellar medium. The optical spectroscopy of CH is limited by interstellar extinction, whereas far-infrared observations provide an integral view t
Externí odkaz:
http://arxiv.org/abs/1804.04707