Updated: 8 July 2023

Research Summary

A 2011 research narrative can be read here.

Faculty Research, 2014−present

• Cosmic Ultraviolet Baryon Survey (CUBS; HST GO-15163), led by Dr. Hsiao-Wen Chen, The University of Chicago
• Qu et al. 2023. "The Cosmic Ultraviolet Baryon Survey (CUBS) VI: Environmental Dependence of Circumgalactic Medium Properties at z ≤ 1", MNRAS, 524, 512
• Chen, M. C. et al. 2023. "Empirical Constraints on the Turbulence in QSO Host Nebulae from Velocity Structure Function Measurements", MNRAS, 518, 2
• Qu et al. 2022, "The Cosmic Ultraviolet Baryon Survey (CUBS) V. On the Thermodynamic Properties of the Cool Circumgalactic Medium at z ≤ 1", MNRAS, 416, 4
• Boettcher et al. 2022, "Discovery of a Damped Lyα Absorber Originating in a Spectacular Interacting Dwarf Galaxy Pair at z = 0026", ApJ, 926L, 2
• Cooper et al. 2021, "The Cosmic Ultraviolet Baryon Survey (CUBS) IV. The Complex Multiphase Circumgalactic Medium as Revealed by Partial Lyman Limit Systems", MNRAS, 308, 3
• Zahedy et al. 2021, "The Cosmic Ultraviolet Baryon Survey (CUBS) III. Physical Properties and Elemental Abundances of Lyman Limit Systems at z < 1", MNRAS, 506, 877
• Boettcher et al. 2021, "The Cosmic Ultraviolet Baryon Survey (CUBS) II. Discovery of an H₂-Bearing DLA in the Vicinity of an Early-Type Galaxy at z = 0.576", ApJ, 913, 18
• Chen et al. 2020, "The Cosmic Ultraviolet Baryon Survey (CUBS) I. Overview and the Diverse Environments of Lyman Limit Systems at z < 1", MNRAS, 497, 498
• COS Circumgalactic Compendium (CCC; HST AR-15634), led by Dr. Nicolas Lehner, University of Notre Dame, IN
• Gibson et al. 2021, "The COS CGM Compendium (CCC). IV: Effects of Varying Ionization Backgrounds on Metallicity Determinations in the z < 1 Circumgalactic Medium", AJ, 164, 9
• Lehner et al. 2019, "The COS CGM Compendium (CCC). III: Metallicities and Physical Properties of the Cool Circumgalactic Medium at z < 1", ApJ, 887, 5
• Wotta et al. 2019, "The COS CGM Compendium (CCC). II: Metallicities of the Partial and Lyman Limit Systems at z < 1", ApJ, 872, 81
• Lehner et al. 2018, "The COS CGM Compendium (CCC). I: Survey Design and Initial Result", ApJ, 866, 33
• Leveraging machine learning to study quasar absorption lines, led by Dr. Simeon Bird, University of California at Riverside
• Monadi et al. 2023, " Machine Learning Uncovers the Universe's Hidden Gems: A Comprehensive Catalogue of C IV Absorption Lines in SDSS DR12", submitted to MNRAS, arXiv:2305.00023
• Bimodal Absorption System Imaging Campaign (BASIC), led by Dr. Nicolas Lehner, University of Notre Dame, IN
• Berg et al. 2022, "The Bimodal Absorption System Imaging Campaign (BASIC) I. A Dual Population of Low-Metallicity Absorbers at z < 1", ApJ, 944, 101
• Cool galactic winds and gas accretion probed by GOTOQs (NSF AST-1715630), led by Dr. Kate Rubin, San Diego State University, CA
• Rubin et al. 2021. "On the Kinematics of Cold, Metal-Enriched Galactic Fountain Flows in Nearby Star-Forming Galaxies", ApJ, 936, 171

MIT Postdoctoral Research, 2009−2013

Precious Metals in SDSS Quasar Spectra (igmabsorbers.info)

• Description:
• Survey SDSS DR7 quasar spectra for common metal lines: C IV, Mg II, and Si IV.
• Generate catalogs for fair, apples-to-apples comparisons with z < 1 HST (UV) and z > 5 FIRE (infrared) catalogs.
• Perform usual IGM analyses on equivalent width frequency distributions, co-moving line densities, etc.
• Collaborators: Dr. Robert Simcoe, Melodie Kao, John O'Meara, Eduardo Seyffert, and J. Xavier Prochaska
• Publication and Presentation:
3. Paper II. "Tracking the Evolution of Strong, 0.4 < z < 2.3 Mg II Absorbers with Thousands of Systems," (Seyffert et al. 2013, arXiv:1308.5971, submitted to ApJ; PDF).
2. "Tracking the Evolution of Strong, 1.5 < z < 4.5 C IV Absorbers with Thousands of Systems":
   1. UC Irvine Astrophysics Seminar, January 2013 (seminar).
   1. Caltech Tea Talk, November 2012 (seminar).
   1. UCLA Journal Club, October 2012 (seminar).
   1. Carnegie Observatories, September 2012 (seminar).
   4. Leiden Observatory, August 2012 (seminar).
   3. MPIA Galaxy Coffee, July 2012 (seminar).
   2. LERMA, Observatoire de Paris, July 2012 (seminar).
   1. Yale Center for Astronomy and Astrophysics, May 2012 (seminar).
1. Paper I. "Tracking the Evolution of Strong, 1.5 < z < 4.5 C IV Absorbers with Thousands of Systems," (Cooksey et al. 2013, ApJ, 763, 37 PDF).

Seeking the Lost Interstellar Medium of Red-Sequence Galaxies

• Description:
• Observe pairs of z ≈ 0.25 red-sequence galaxies with close (in angular separation), background quasars
• Measure incidence of Mg II and Fe II absorption in gaseous halo (out to a few hundred kiloparsecs)
• Compare galaxies' (stellar) metallicities, abundances, and ages for those that do and do not have halo gas
• Determine whether any properties help identify the mechanism that expelled the galaxies interstellar medium
• Collaborator: Dr. Robert Simcoe
• Presentation:
1. "Revealing the Enrichment of the IGM." presentation (PDF), The Cosmic Odyssey of the Elements, Aegina, Greece, June 2008. [Actually, this pilot study was the inspiration for "Seeking the Lost Interstellar Medium of Red-Sequence Galaxies"; the talk abstract and slides can be found here.]

Polluting the IGM: the Extended Gaseous Halos of z ≈ 2.5 LGBs

• Description:
• Measure redshifts of galaxies with small angular separations from background quasars, for which we have high-S/N, high-resolution spectra
• Construct detailed models of the absorbing gas clouds via Voigt-profile fitting, Starburst99, and CLOUDY ionization modeling
• Characterize the physical properties of the gas with respect to its host galaxy.
• Collaborator: Dr. Robert Simcoe

^* Postdoctoral fellow for Dr. Robert Simcoe from 2009 to 2010, then an NSF Astronomy & Astrophysics Postdoctoral Fellow (AST-1003139) from 2010 to 2013.

UCSC Doctoral Project, 2005−2009

Probing the Chemical Composition of the z < 1 Intergalactic Medium with Observations and Simulations

• Description:
• Identify all C IV and Si IV absorption in the HST STIS and GHRS archives (igmabsorbers.info)
• Investigate the galactic environments of low-redshift IGM absorption systems
• Compare and contrast observations with simulations to characterize feedback processes
• Measure H I column densities for metal-strong damped Lyα systems
• Explore IGM-galaxy connection
• Advisor: J. Xavier Prochaska
• Publication ands Presentations:
6. "The Last Eight-Billion Years of Intergalactic C IV and Si IV Evolution," presented at numerous colloquia and conferences (see the UCSC Doctoral Project page for complete information).
5. Cooksey, Prochaska, Thom, and Chen, "The Last Eight-Billion Years of Intergalactic Si IV Evolution," (2011, ApJ, 729, 87; online, PDF).
4. Cooksey, "Probing the Chemical Composition of the z < 1 Intergalactic Medium with Observations and Simulations," (2009, dissertation PDF).
3. Cooksey, Thom, Prochaska, and Chen, "The Last Eight-Billion Years of Intergalactic C IV Evolution," (2010, ApJ, 708, 868; online, PDF [published version but our PDF is formatted better]).
2. "The Last Eight-Billion Years of Intergalactic C IV Evolution," conference presentation (PDF) from The Chemical Enrichment of the Intergalactic Medium, Leiden, The Netherlands, May 25−19, 2009.
1. "Revealing the Enrichment of the IGM." presentation (PDF), The Cosmic Odyssey of the Elements, Aegina, Greece, June 2008. [Actually, this project was the inspiration for the NSF AAPF project "Seeking the Lost Interstellar Medium of Red-Sequence Galaxies" described above and here.]

UCSC Master Project, 2004−2005

Characterizing the Low-redshift Intergalactic Medium towards PKS1302−102

• Description: detailed analysis of ultraviolet spectra of the low-redshift quasar PKS1302−102, focusing on metal-line systems (e.g. O VI) and strong Lyα absorbers; ionization modeling; complementary galaxy survey
• Advisor: J. Xavier Prochaska
• Publications and Presentations:
4. Cooksey and Prochaska, "Metal-line System Survey: Characterizing the Low-redshift IGM," (conference proceeding PDF 2008, Astronomy, Astrophysics & Space Science).
3. "Metal-line System Survey: Characterizing the Low-z IGM," presentation (PDF), the first Space Astronomy: The UV Window to the Universe, El Escorial, Spain, May 2007.
2. Cooksey et al., "Characterizing the Low-redshift Intergalactic Medium towards PKS1302−102," (PDF; 2008 ApJ, 676, 262).
1. Cooksey and Prochaska,"Searching for O VI Absorption Systems toward PKS1302−102," poster (PDF), 205th meeting of the American Astronomical Society, San Diego, CA, January 2005.

VU Senior Thesis

The Formation of Substellar Companions due to Protostellar Disk Instabilities:
Modeling the Effects of the Gravitational Environment

• Description: studying the effects of a "cluster" of stars around a protostellar disk model, previously studied in isolation
• Advisor: Brian K. Pickett
• Publication:
1. Thesis (PDF).

CERN REU 2002

Calibration of the Compact Muon Solenoid Hadron Calorimeter

• Description: calibrating the response of the hadron calorimeter to variations in temperature
• Advisors: Richard Kellogg and Pawel de Barbaro

LIGO REU 2001

Gravitational-wave Signal Simulation for LIGO

• Description: Signal simulation program to complement the end-to-end time domain simulation, which models the response of the entire LIGO system; simulates gravitational-wave signal from coalescing compact binaries and spin-down supernovae
• Advisor: Hiroaki Yamamoto
• Publication and Presentation:
2. "Gravitation-wave Signal Simulation for LIGO," 2002, 16th National Conference on Undergraduate Research, University of Wisconsin−Whitewater (presentation PDF and proceeding below).
1. Cooksey and Yamamoto, "Gravitation-wave Signal Simulation for LIGO," 2002, LIGO Document Control Center, (PDF; also NCUR proceeding).

CTIO REU 2001

Star Formation in the Isolated Molecular Cloud NGC 1788

• Description: multi-wavelength survey of objects in the isolated molecular cloud NGC 1788; ROSAT (X-ray), CTIO observations (optical and near-infrared), 2MASS (near-infrared), Hipparcos (proper motions)
• Advisors:Don Hoard and Stefanie Wachter
• Publications and Presentation:
3. Alcalá et al., "Multi-wavelength Observations of the Star-forming Region in L1616." 2004, A&A, 516, 677 (PDF).
2. Alcalá et al., "X-ray and Optical Observations of NGC 1788." 2003, ASPC, 287, 140 (conference proceeding; PDF).
1. Cooksey, Hoard, and Wachter,"Star Formation in the Isolated Molecular Cloud NGC 1788 (LDN 1616)," poster, 199th meeting of the American Astronomical Society, Washington, D.C., January 2002.

Observations of RR Lyrae with the Schmidt Telescope

• Description: supplemental observing program in order to learn how to observe; collect data on RR Lyrae variability for Andrew Layden
• Publication:
1. Day et al., "Light and Color Curves of Six Field RR Lyrae Variable Stars." 2002, PASP, 114, 645 (PDF).
• Also see REU participant Rudy Montez's RR Lyrae page.

VU Research Assistant 2000

Optical Variability of Proto-Planetary Nebulae

• Description: part of a long-term observation program of proto-planetary nebulae, an intermediate phase of the low-mass stellar lifecycle (post-AGB but not yet a planetary nebulae); observations from VU 16" telescope; periodicity analysis
• Advisor: Bruce Hrivnak
• Poster Presentations:
2. "A Long-Term Study of Photometric Variability in Proto-Planetary Nebulae," Rush et al., 203rd meeting of the American Astronomical Society, Atlanta, GA, May 2003.
1. "A Long-Term Study of Photometric Variability in Proto-Planetary Nebulae," Klinke et al., 202nd meeting of the American Astronomical Society, Nashville, TN, January 2003.