The Evolution of and Starburst-AGN Connection in Luminous and Ultraluminous Infrared Galaxies

287 Pages·2017·8.36 MB·English

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Dissertations, Theses, and Capstone Projects CUNY Graduate Center
6-2014
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Stephanie L. Fiorenza
Graduate Center, City University of New York
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THE EVOLUTION OF AND STARBURST-
AGN CONNECTION IN LUMINOUS AND
ULTRALUMINOUS INFRARED GALAXIES
AND
THEIR LINK TO GLOBULAR CLUSTER
FORMATION

by

Stephanie Lynn Fiorenza

A dissertation submitted to the Graduate Faculty in Physics in partial fulfillment of the
requirements for the degree of Doctor of Philosophy, The City University of New York
2014
i
© 2014

Stephanie Lynn Fiorenza

All Rights Reserved

ii
This manuscript has been read and accepted for
the Graduate Faculty in Physics in satisfaction
of the dissertation requirement for the degree of
Doctor of Philosophy.

Dr. Charles T. Liu

__________ _____________________
Date Chair of Examining Committee

Dr. Steven G. Greenbaum

______________ ____________________________
Date Executive Officer

Dr. Alfred Levine
Dr.  Matthew  O’Dowd
Dr. Emily Rice
Dr. Sivarani Thirupathi
________________________________________________
Supervisory Committee

THE CITY UNIVERSITY OF NEW YORK
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Abstract

THE EVOLUTION OF AND STARBURST-
AGN CONNECTION IN LUMINOUS AND
ULTRALUMINOUS INFRARED GALAXIES
AND
THEIR LINK TO GLOBULAR CLUSTER
FORMATION

BY

STEPHANIE LYNN FIORENZA

Advisor: Dr. Charles T. Liu

The evolutionary connection between nuclear starbursts and active galactic nuclei (AGN) in
luminous infrared galaxies (LIRGs; 1011o<oL o< 1012 L ) and ultraluminous infrared galaxies
IR

(ULIRGs; 1012 < L < 1013 L ), which result from galaxy interactions and mergers and produce
IR

the bulk of their radiation as infrared (IR) emission, is not well understood. To this effort, I first
spectroscopically examine U/LIRGs (1011 < L < 1013 L ) within the IRAS 2 Jansky Redshift
IR ⊙
Survey with 0.05 < z < 0.16.
Using new spectrophotometric data, I classify the primary source of IR radiation as being
a nuclear starburst or a type of AGN by using the Baldwin-Phillips-Terlevich (BPT) diagrams. I
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show that for the U/LIRGs in my sample the properties that describe their nuclear starbursts and
AGN (e.g. star formation rate (SFR), L[O III], optical D parameter, D4000, and EW(Hδ)) are
independent of one another, ensuring that no biases affect correlations between these properties
and objects' locations on the BPT diagrams. I then derive evolutionary paths on the BPT
diagram involving [N II]/Hα that are based on how these properties vary between two U/LIRGs
positioned at the end-points. The paths involve U/LIRGs that decrease in SFR and increase in
AGN activity. Paths with U/LIRGs that evolve into high luminosity AGN likely do so due to
recent, strong starbursts.
Second, to study how the properties of the IR power sources in U/LIRGs vary, I use a
combination of photometric data points that I carefully measure (using photometry from SDSS,
2MASS, WISE, and Spitzer) and that I retrieve from catalogues (IRAS, AKARI, and ISO) to
perform UV to FIR SED-fitting with CIGALE (Code Investigating GALaxy Emission) for 34
U/LIRGs from the IRAS 2 Jy Redshift Survey with 0.01 < z < 0.16. CIGALE allows for the
estimation of numerous physical properties by means of a Bayesian-like analysis, but for this
work I focus on derived outputs for the SFR, AGN contribution, D4000, stellar mass (M ),
star
young stellar population age (i.e. the age of the most recent starburst activity), starburst mass
fraction, luminosity absorbed by dust, and stellar mass-weighted age. Comparing the properties
of the IR power sources in U/LIRGs with age-related properties provides clues as to which type
of IR power source forms first and how starburst age varies with starburst/AGN strength.
I find evidence that the nuclear starburst forms first in U/LIRGs, and also find that
U/LIRGs with relatively similar SFRs show increased AGN activity if they are older. However, I
also find that a young U/LIRG can show a relatively large amount of AGN activity if a very
large starburst is present. Then, I quantify the timescales at which the starburst activity in my
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U/LIRGs evolves with the use of the Tukey-Kramer method of statistical analysis, and fit an
exponential curve to the data to describe the expected amount of decrease in SFR seen for a
U/LIRG in my sample over a given change in starburst age. Finally, I find evidence that the
stellar mass and starburst mass fractions influence whether a U/LIRG in my sample will have a
strong AGN and SFR, respectively. I compare the SFR-M relationship seen in my sample with
star
those predicted by models and found from previous observations. I find that the U/LIRGs with
older starbursts (>125 Myr) agree with previous results, while those with younger starbursts
show a large dispersion in M . I conclude that this is supporting evidence that the star
star
formation histories and timescales at which the IR power sources in U/LIRGs evolve are
responsible for the scatter found for the SFR-M relationship.
star
U/LIRGs that form from merging gas-rich disk galaxies could also represent a stage of
galaxy evolution involving heavy formation of globular clusters (GCs). It has been suggested
that a large number of stellar clusters form during the merging of two gas-rich disk galaxies,
leading to open and young massive clusters with the latter likely evolving into GCs. Furthering
our understanding of GC formation can uncover the connection between GCs and their host
galaxies, which could, at some point during their formation or evolution, be U/LIRGs. To
understand GC formation in the context of hierarchical galaxy formation, it is necessary to
understand the origin of their abundance patterns. To this effort, I use SDSS spectra from Data
Release 8 and 9 to estimate carbon (C) abundances for five GCs by matching synthetic spectra,
created with TURBOSPECTRUM using atmospheric parameters derived from the Segue Stellar
Parameter Pipeline, with observed spectra at the CH G-band feature. I find large spreads in the C
abundances throughout the color magnitude diagrams of the GCs, which serves as evidence for
multiple stellar populations, in contrast to standard models of GC formation.
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Acknowledgements

I would like to thank my parents, Todd and Donna, for always being there for me, and for always
believing that I could do anything I wanted. You both gave me more than I could have ever
imagined of both the stuff that money can buy and the things in life that are even harder to find. I
want to thank my brother, Mike, for helping me with computer glitches and discussing
programming in Python with me – and you know you always have fun doing it! I want to thank
my sister, Mallory, for her encouraging words over the years.
I also would like to thank my entire extended family for their encouragement, and give a
special thank you to Randy Fiorenza, my Godfather and uncle, for all of the financial and moral
support he has given me over the years. Without your generosity my life would be very different.
I would like to thank all of the research advisors that I have had the pleasure of working
with: Dr. Charles Liu, my thesis advisor, Dr. Tsutomu Takeuchi of Nagoya University in Japan,
and Dr. Sivarani Thirupathi of the Indian Institute for Astrophysics in Bangalore, India. I also
want to thank Dr. Timothy Beers for giving me an opportunity to continue the work I began in
India at the National Optical Astronomy Observatory in Tucson, AZ. I also wish to thank Dr.
Kasia Malek of Nagoya University for the many useful comments and scientific discussions.
I am also appreciative of the members of my thesis committee for taking the time to read
my dissertation and prepare thoughtful questions for my defense: my thesis advisor, Dr. Charles
Liu,  as  well  as  Dr.  Alfred  Levine,  Dr.  Matthew  O’Dowd,  Dr.  Emily  Rice,  and Dr. Sivarani
Thirupathi.
Finally, I would like to thank everyone who believed in me, but also all of those who did
not. It has been fun proving you wrong!
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Table of Contents
Chapter 1: Introduction to Luminous and Ultraluminous Infrared Galaxies ................... 1
1.1 What are Luminous and Ultraluminous Infrared Galaxies? ...................................................... 2
1.2 Overview of Luminous and Ultraluminous Infrared Galaxies ................................................... 4
1.2.1 Discovery ................................................................................................................................................................ 4
1.2.2 Interactions and Merging in U/LIRGs ......................................................................................................... 6
1.2.3 Nuclear Starbursts and AGN as Nuclear Power Sources in U/LIRGs ............................................ 8
1.2.4 Understanding the Starburst-AGN Connection in U/LIRGs ........................................................... 10
Chapter 2: Evolutionary Paths along the BPT Diagram for Luminous and
Ultraluminous Infrared Galaxies ................................................................................................... 15
2.1 Abstract ....................................................................................................................................................... 16
2.2 Introduction .............................................................................................................................................. 17
2.3 Sample and Observations ..................................................................................................................... 20
2.3.1 IRAS 2 Jy Redshift Survey.............................................................................................................................. 20
2.3.2 Optical Spectrophotometry ......................................................................................................................... 21
2.3.3 Spectral Corrections Using Emission-line Measurements .............................................................. 26
2.3.4 Measurement of Emission Lines ................................................................................................................ 29
2.4 Spectroscopic Classification ................................................................................................................ 31
2.5 Determination of Spectroscopic Properties .................................................................................. 36
2.5.1 Star Formation Rates ...................................................................................................................................... 37
2.5.2 AGN Strength ..................................................................................................................................................... 38
2.5.2.1 [O III] Luminosity .................................................................................................................................... 38
2.5.2.2 Optical D Parameter ............................................................................................................................... 40
2.5.3 Stellar Population Age .................................................................................................................................... 41
2.5.4 Recent Starburst Activity .............................................................................................................................. 42
2.5.5 A Comparison of Total and Corrected Flux Values ............................................................................ 43
2.6 Discussion .................................................................................................................................................. 45
2.6.1 Trends of Measured Properties ................................................................................................................. 45
2.6.2 Evolutionary Paths along the BPT Diagram .......................................................................................... 54
2.7 Summary ..................................................................................................................................................... 60
Chapter 3: Properties of Luminous and Ultraluminous Infrared Galaxies Derived
from SED-fitting with CIGALE .......................................................................................................... 63
3.1 Abstract ....................................................................................................................................................... 64
3.2 Introduction .............................................................................................................................................. 66
3.3 Sample and Data ...................................................................................................................................... 72
3.4 SED-fitting Technique: Description of the CIGALE Code ............................................................ 91
3.4.1 Stellar Populations and Star Formation Histories.............................................................................. 92
3.4.2 Dust Attenuation and Infrared Emission ............................................................................................... 95
3.4.3 Active Galactic Nucleus Contribution ...................................................................................................... 98
3.4.4 Construction of Mock Catalogue Dedicated to the Sample to Check Reliability of
Parameters.................................................................................................................................................................. 101
3.5 Results of the SED-fitting Analysis .................................................................................................. 103
3.5.1 Analysis of Results for the Mock Catalogue ....................................................................................... 103
3.5.2 Analysis of Results for the U/LIRG Sample ........................................................................................ 112
3.6 Discussion ............................................................................................................................................... 123
3.6.1 Relative Ages of U/LIRGs of Varying Star Formation Rate and AGN Contribution ........... 123
3.6.2 Timescales for the Evolution of U/LIRGs ............................................................................................ 130
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3.6.3 The Influence of Stellar Mass on Star Formation Rate .................................................................. 141
3.7 Summary .................................................................................................................................................. 148
Chapter 4: The Connection Between Globular Cluster Formation and Galaxy
Evolution ............................................................................................................................................. 151
4.1 Introduction to Globular Cluster Formation .............................................................................. 152
4.2 Insights into Galaxy Evolution from Studies of Globular Cluster Formation .................. 154
Chapter 5: Carbon Abundances from SDSS Globular Clusters: Exploring the Origin in
the Large Spread in [C/Fe] ............................................................................................................ 157
5.1 Abstract .................................................................................................................................................... 158
5.2 Introduction ........................................................................................................................................... 159
5.3 Sample and Data ................................................................................................................................... 163
5.4 Carbon Abundance Estimation ........................................................................................................ 168
5.5 Results and Discussion ....................................................................................................................... 171
5.6 Summary .................................................................................................................................................. 179
5.7 Follow-Up Study .................................................................................................................................... 182
Chapter 6: Summary and Future Work .................................................................................... 217
Appendix A: Discussion of How the BPT Diagrams Distinguish between Star-forming
Galaxies and those with Seyfert- and LINER-type AGN ....................................................... 227
Appendix B: Spectral Energy Distributions for U/LIRGs with Measured Photometric
Points and Data from the Literature ......................................................................................... 230
Appendix C: Best-Fit Model Spectral Energy Distributions from CIGALE .................... 249
References .......................................................................................................................................... 257
Autobiographical Statement ........................................................................................................ 272

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