Updated: 12 April 2012

Research Summary

A research narrative can be read here.

Current, 2009−present

Precious Metals in SDSS Quasar Spectra

• Description:
• Survey SDSS DR7 quasar spectra for common metal lines: C IV, Si IV, Mg II, and Ca II.
• Generate catalogs for fair, apples-to-apples comparisions 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: Robert Simcoe, Melodie Kao, John M. O'Meara, Eduardo Seyffert, and Jason X. Prochaska
• Publication and Presentation:
2. "Tracking the Evolution of Strong, 1.5 < z < 4.5, C IV Absorbers with Thousands of Systems," presentation, Yale Center for Astronomy and Astrophysics seminar, 8 May 2012.
1. Paper I. "Tracking the Evolution of Strong, 1.5 < z < 4.5, C IV Absorbers with Thousands of Systems," (2012, submitted to ApJ; 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 MgII and FeII 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: 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: Robert Simcoe

^* Postdoctoral fellow for Rob Simcoe from 2009 to 2010, then an NSF Astronomy & Astrophysics Postdoctoral Fellow 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 CIV and SiIV absorption in the HST STIS and GHRS archives
• Investigate the galactic environments of low-redshift IGM absorption systems
• Compare and contrast observations with simulations to characterize feedback processes
• Measure HI 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 CIV and SiIV 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 SiIV Evolution," (2011, ApJ, 729, 87; 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 CIV Evolution," (2010, ApJ, 708, 868; PDF [published version but our PDF is formatted better]).
2. "The Last Eight-Billion Years of Intergalactic CIV 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. OVI) 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 OVI 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.