Dynamical evolution of local gas-rich galaxy mergers from NIR spectroscopy [Elektronische Ressource] / vorgelegt von Kalliopi-Maria Dasyra

Dasyra, Kalliopi-Maria

Sujets

• Astronomie

Informations

• Publié par: ludwig-maximilians-universitat_munchen
• Publié le: 01 janvier 2006
• Nombre de lectures: 8
• Langue: English
• Poids de l'ouvrage: 4 Mo

Extrait

Dynamical evolution of local
gas-rich galaxy mergers
from NIR spectroscopy
DISSERTATION
der Fakult at fur Physik der Ludwigs-Maximilians-Universit at Munc hen
zur Erlangung des Grades
Doktor der Naturwissenschaften
Dr. rer. nat.
vorgelegt von
Kalliopi-Maria DASYRA aus Athen, Griechenland
Munchen, den 1. Mai 2006Erstgutachter : Prof. Dr. Reinhard Genzel
Zweitgutachter : Prof. Dr. Andreas Burkert
Tag der mundlic hen Prufung : 23 Oktober 2006Contents
Resume 3
1 Introduction: Galaxy mergers in a general framework 5
1.1 The role of mergers in galaxy evolution . . . . . . . . . . . . . 5
1.2 The predicted evolution of galaxy mergers . . . . . . . . . . . . 6
1.3 Observational classi cation of mergers . . . . . . . . . . . . . . 11
1.4 Aim, observations, and techiques of this work . . . . . . . . . . 12
2 Pre-coalescence ultraluminous merger phases 17
(Conditions for ultraluminous activity in local mergers) . . . . . . . 17
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.2 Observations and Data Reduction . . . . . . . . . . . . . . . . 19
2.3 Structural parameters . . . . . . . . . . . . . . . . . . . . . . . 27
2.4 ULIRG stellar velocities and black hole masses . . . . . . . . . 33
2.5 Progenitor mass ratios . . . . . . . . . . . . . . . . . . . . . . . 36
2.6 A model for the evolution of the mass ratio . . . . . . . . . . . 41
2.7 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
3 Post-coalescence ultraluminous merger phases 45
(Evolution of the stellar kinematics during the ULIRG phases) . . . 45
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
3.2 Observations And Data Reduction . . . . . . . . . . . . . . . . 48
3.2.1 Data Acquisition And Analysis . . . . . . . . . . . . . . 48
3.2.2 Pre- and Post-coalescence Sample Classi cation . . . . . 56
3.3 Traces of Evolution In The Stellar Kinematics . . . . . . . . . . 57
3.4 Origin Of The ULIRG Remnants . . . . . . . . . . . . . . . . . 60
3.5 End Products Of ULIRGs . . . . . . . . . . . . . . . . . . . . . 62
3.5.1 The Masses Of Ultraluminous Merger Remnants . . . . 62
3.5.2 ULIRGs And The Fundamental Plane Of Es . . . . . . 63
3.5.3 Discussion: The role of ULIRGs in the formation of Es . 68
3.5.4 Wavelength Dependence Of The Stellar Measurement 71
3.6 Black Holes in ULIRGs . . . . . . . . . . . . . . . . . . . . . . 73
1Contents
3.6.1 A Picture Of The M - Relation Time Evolution . . . 73BH
3.6.2 Black Hole Sizes and Accretions Rates . . . . . . . . . . 76
3.7 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
4 A scenario of QSO phases 79
(Host dynamics and origin of Palomar-Green QSOs) . . . . . . . . . 79
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
4.2 Observations and data reduction . . . . . . . . . . . . . . . . . 82
4.2.1 Sample selection . . . . . . . . . . . . . . . . . . . . . . 82
4.2.2 Data acquisition and analysis . . . . . . . . . . . . . . . 86
4.3 Results. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
4.3.1 Host-galaxy dynamical properties . . . . . . . . . . . . . 92
4.3.2 Black hole properties . . . . . . . . . . . . . . . . . . . . 93
4.4 ULIRG vs. (IR-excess) PG QSO dynamics. . . . . . . . . . . . 99
4.5 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
4.5.1 Relation of PG QSOs to gas-rich mergers . . . . . . . . 100
4.5.2 Relation of PG to other QSO populations . . . . 104
4.6 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
5 Conclusions 107
Acknowledgements 110
APPENDIX 111
Bibliography 112
2Resume / Zusammenfassung
Thisstudyaimedtotracehowthestellarkinematicsevolvewhentwogas-rich
galaxiesmerge. Tostudytheevolutionofsuchmergers, Very-Large-Telescope
observations were performed for the best-suited galaxy population in the lo-
cal Universe, the Ultraluminous Infrared Galaxies (ULIRGs). The prodigious
infrared emission in ULIRGs originates from the intense star formation that
occurswhenlargeamountsgasaredriventothecenterofthemergingsystem.
We acquired near-infrared H- and K-band spectroscopic data of 54 ULIRGs
atvariousmergerphases;approximatelyhalfofthesourcesinoursamplehave
two distinct nuclei. For each source, we derived the stellar kinematics from
the high-resolution spectra by studying the pro le of the stellar CO absorp-
tion lines. The shape of the pro le along various slit positions enables us to
measure the rotational velocity, V and velocity dispersion, , and to com-rot
putethestellarandblackhole(BH)masses. WendthatULIRGsaremostly
triggered by mergers of roughly equal-mass galaxies. Their mean velocity dis-
1persion equals 150( 33) km s . A possible trend of dynamical heating of
the galaxies as the merger evolves is observed at marginal statistical levels.
The kinematic, structural, and photometric properties of ULIRGs indicate
that they are dispersion-dominated systems and that they mainly result in
10 11the formation of 10 -10 M mass elliptical galaxies (Es). Their locus on
thefundamentalplaneofEsindicatesthattheirendproductsaretypicallyin-
7 8consistent with giant Es. The BH masses in ULIRGs are of the order 10 - 10
M . To investigate whether ULIRGs go through quasar (QSO) phases dur-
ing their evolution, we have acquired similar data for 12 local Palomar-Green
(PG)QSOs. ThemeanbulgedispersionofthePGQSOsinoursampleequals
1186 (24) km s . The measurement of the stellar dispersion in QSOs en-
ables us to place them on signi cant observational diagrams, such as the local
BHmass andhost-galaxybulgerelationandthe fundamentalplaneofEs. On
the latter, PG QSOs are located between the regions occupied by moderate-
11mass and giant Es. Their bulge and BH masses are on the order of 10 M
7 8and 510 10 M respectively. PG QSOs seem to be triggered by gas-
rich mergers, and therefore likely formed in an analogous manner to ULIRGs.
8 9However, other local QSOs with supermassive black holes of 510 10 M