Universität zu Köln

García Fuentes, Pablo (2015). The Warm ISM in the Sgr A Complex: Mid-J CO, Atomic Carbon, Ionized Atomic Carbon, and Ionized Nitrogen Line Observations with the Herschel-HIFI and the NANTEN2/SMART Telescopes. PhD thesis, Universität zu Köln.

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Abstract

The interstellar medium (ISM) in the few central hundred parsecs of the Galaxy has physical properties that differ strongly from the rest of the ISM in the Galaxy. In the present work, large-scale submillimeter heterodyne observations towards the Sgr A Complex (located in the Galactic Center) covering approx. 300 arcminutes-square, obtained in the frame of the Herschel EXtraGALactic Guaranteed Time key Program (HEXGAL) with the Herschel-HIFI satellite and complementary data with the NANTEN2/SMART telescope are presented. The observed species are: CO(J=4-3) at 461.0 GHz observed with the NANTEN2/SMART telescope, [CI] 3P1 - 3P0 at 492.2 GHz, [CI] 3P2 - 3P1 at 809.3 GHz, [NII] 3P1 - 3P0 at 1461.1 GHz, and [CII] 2P3/2 - 2P1/2 at 1900.5 GHz observed with the Herschel-HIFI satellite. The observations are presented in 1 km/s spectral resolution, and spatial resolutions ranging from 46 to 28 arcseconds. The frequency bandwidth of the three lower frequency lines largely allows to cover the emission found within +-200 km/s, while in the two high frequency lines, the upper LSR velocity is limited to +94 km/s for the [NII] line due to baseline instabilities, and to +144 km/s for the [CII] line, due to the available spectrometer bandwidth. The spatial distribution of the emission in all lines is very widespread. The bulk of the carbon monoxide emission is found toward Galactic latitudes below the Galactic plane, and all major known molecular clouds are identified. Both neutral atomic carbon lines have their brightest emission associated with the +50 km/s cloud. Their spatial distribution at this LSR velocity describes a crescent-shape structure, which is probably the result of interaction with the energetic event (one or several supernovae explosions) that gave origin to the non thermal Sgr A-East source. The [CII] and [NII] emissions have most of their flux associated to the thermal Arched-Filaments and the H-Region, with also bright spots in [CII] emission towards the Central Nuclear Disk. Out of the large number of astronomical sources (Arched-Filaments, the H-Region, more than ten molecular clouds, the Circum Nuclear Disk, the Sickle H II region, gas streamers, high velocity gas, and high velocity compact clumps) detected in these datasets, the Arched-Filaments and the High Velocity Gas Clouds were selected for a preliminary analysis of their physical conditions, while future work related to the +50 km/s and +20 km/s Clouds is outlined.

Item Type:	Thesis (PhD thesis)
Creators:	Creators Email ORCID ORCID Put Code García Fuentes, Pablo pablo@ph1.uni-koeln.de UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-63583
Date:	11 May 2015
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Physics > Institute of Physics I
Subjects:	Physics
Uncontrolled Keywords:	Keywords Language ISM, Atoms, Molecules, Clouds, Galaxy, Galactic Center English
Date of oral exam:	25 June 2015
Referee:	Name Academic Title Stutzki, Jürgen Prof. Dr. Trebst, Simon Prof. Dr.
Projects:	SFB956 project
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/6358