Gravitationally Lensed, High-Redshift Starburst Galaxies
Typ
Examensarbete för masterexamen
Program
Publicerad
2022
Författare
Bredberg, Markus
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Local, massive galaxies are seen to host very old stellar populations. This indi cates that a significant fraction of the stellar mass was formed during early epochs.
The discovery of intense starburst galaxies at high redshifts have suggested that
such galaxies are part of an evolutionary sequence towards today’s massive galax ies. This master’s thesis provides an introductory theoretical background in the
history and very basics of the study of galaxies, techniques and methods in ob servational radio astronomy, and evolution of distant, massive galaxies. After this
summary, two redshift z=2.5-2.8 sources, discovered by the South Pole Telescope
(SPT), are analysed through the visibility-based lens modeling tool visilens.
Spectra and galaxy-galaxy gravitational lensing models are obtained from ∼ 0.1
00
resolution data from the Atacama Large Millimeter/submillimeter Array of the
CO(3-2) line from SPT0125-47 and SPT2134-50. Results indicate magnifications
of µ = 15.4 ± 0.9 for SPT0125-47 and µ = 20.2 ± 2.9 for SPT2134-50. The cor responding FWHMs are (380 ± 47) km s−1 and (550 ± 87) km s−1
, which leads to
intrinsic line luminosities L
0
CO(3−2) = (5.1 ± 0.84)1010 K km s−1 pc2 and L
0
CO(3−2) =
(1.5 ± 0.31)1010 K km s−1 pc2
, respectively. From previous derived relations, the gas
masses are determined to Mgas = (3.4±1.1)1010 M and Mgas = (1.6±0.49)1010 M
respectively. The molecular gas mass estimates are similar to dynamical estimates
assuming rotation, which suggests that the inner region of these galaxies are gas dominated. A skewed emission line and magnification for SPT0125-47 suggests that
this source is either a rotating disc or a system of galaxy mergers.
Beskrivning
Ämne/nyckelord
high-redshift — Gravitational lensing: strong — Tech niques: interferometric — Telescopes: ALMA