curriculum vitae


My CV (October 2017): Holz_cv.pdf.


papers


As of Fall 2017 I have published over 100 papers with over 10,000 citations (excluding LIGO collaboration papers to which I have not made significant contributions), and have an h-index greater than 50. My Erdös number is 4 (Erdös→Prasad Tetali→Marc Mézard→Tony Zee→DH) and my Einstein number is also 4 (Einstein→Valentine Bargmann→John Klauder→John Wheeler→DH). My academic genealogy includes Ernest Rutherford/J.J. Thompson→Niels Bohr→John Wheeler→Bob Wald→DH. Most of my papers are available from Google Scholar, ADS (astro), INSPIRE (HEP), and the Los Alamos arXiv.


current research


My current research program revolves around the dawning era of gravitational-wave astronomy, concentrating on the use of compact binaries to probe astrophysics and cosmology. I am a member of the LIGO Scientific Collaboration, and have participated very actively in our many discoveries thus far, including the first detection of a binary black hole coalescence (GW150914) and the first detection of a binary neutron star coalescence (GW170817).


I am also one of the leaders of the DES-GW collaboration (along with Marcelle Soares-Santos, Edo Berger, Josh Frieman, and Jim Annis); we use DECam to follow-up LIGO triggers, looking for potential EM counterparts. We independently discovered the optical transient associated with GW170817.


One of the major reasons I joined LIGO, and helped put together the DECam team, was to be able to use a gravitational-wave standard siren to measure the Hubble constant. And this came to pass beyond my wildest imaginings with GW170817; our results are published here.


Standard sirens have been somewhat of a career obsession (white whale?). Gravitational-wave detections of binary coalescences provide a clean measurement of cosmological distance. There is no distance ladder, nor complicated astronomical calibration. You listen to how loud the gravitational waves are, and how the sound changes with time, and you directly infer the distance to the source. The calibration is provided directly by the theory of general relativity, making this a particularly powerful probe. I have worked extensively on this topic, following-up on Bernie Schutz’s seminal 1986 paper. Scott Hughes and I pointed out in 2005 the particular utility of EM counterparts, and named these sources “standard sirens” (the gravitational wave counterparts of their electromagnetic cousins, “standard candles”). In Dalal et al. 2006 we proposed short GRBs as particularly promising standard sirens, following this up with a wide range of related projects (Cutler & Holz 2009; Hirata et al. 2010; Nissanke et al. 2010, 2011, 2014; see CV linked above for full listing). And then it all came together in 12 hours on August 17, 2017. LIGO/Virgo discovered a binary neutron star associated with a gamma-ray burst, we triggered our follow-up with DECam and discovered the optical counterpart and associated host galaxy (it was also independently discovered by DECam group member Ryan Foley using Swope), and shortly afterwards we made the first standard siren measurement of the Hubble constant.


Beyond standard sirens, I have also been addressing questions such as: how often binary coalescences happen in nature; how we might detect them from either their gravitational wave or electromagnetic emission; how we might use them as multi-messenger sources; and, most importantly, what we will learn from them, including about stellar evolution, black hole formation, gamma-ray burst engines, strong-field general relativity, and the evolution history of the universe. Details below.


Papers written in 2017 (as of Oct 16)


GW astronomy:

Statistical Gravitational Waveform Models: What to Simulate Next?

Z. Doctor, B. Farr, D.E. Holz, & M. Pürrer


Using spin to understand the formation of LIGO's black holes

B. Farr, D.E. Holz, & W. M. Farr


Distance measures in gravitational-wave astrophysics and cosmology

H.-Y. Chen, D.E. Holz, J. Miller, M. Evans, S. Vitale, & J. Creighton

also see our Gravitational Wave Distance Calculator


Where are LIGO's Big Black Holes?

M. Fishbach & D.E. Holz


LIGO/Virgo collaboration:

GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral

B. P. Abbott et al.


Multi-messenger Observations of a Binary Neutron Star Merger

B. P. Abbott et al.


Gravitational Waves and Gamma-Rays from a Binary Neutron Star Merger:

GW170817 and GRB 170817A

B. P. Abbott et al.


A gravitational-wave standard siren measurement of the Hubble constant

B. P. Abbott et al.


DECam collaboration follow-up:

The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. I. Discovery of the Optical Counterpart Using the Dark Energy Camera

M. Soares-Santos, D. E. Holz et al.


The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. II. UV, Optical, and Near-infrared Light Curves and Comparison to Kilonova Models

P. S. Cowperthwaite et al.


The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. III. Optical and UV Spectra of a Blue Kilonova from Fast Polar Ejecta

M. Nicholl et al.


The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. IV. Detection of Near-infrared Signatures of r-process Nucleosynthesis with Gemini-South

R. Chornock et al.


The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. V. Rising X-Ray Emission from an Off-axis Jet

R. Margutti et al.


The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. VI. Radio Constraints on a Relativistic Jet and Predictions for Late-time Emission from the Kilonova Ejecta

K. D. Alexander et al.


The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. VII. Properties of the Host Galaxy and Constraints on the Merger Timescale

P. K. Blanchard et al.


The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. VIII. A Comparison to Cosmological Short-duration Gamma-Ray Bursts

W. Fong et al.



biography


I received my A.B. in physics from Princeton University in 1992, under the mentorship of John Wheeler. My graduate work was at the University of Chicago with Robert Wald. I received my PhD in 1998, and subsequently spent a year as a postdoc at the Albert Einstein Institute (Max Planck Institute for Gravitational Physics) in Potsdam, Germany, as a member of the astrophysical relativity division. From 2000-2002 I was a postdoc at the Kavli Institute for Theoretical Physics in Santa Barbara, after which I returned to Chicago as a Center Fellow at the Kavli Institute for Cosmological Physics. In 2004 I moved to the Los Alamos National Laboratory as a Richard Feynman Fellow in the theoretical astrophysics (T-6) and theoretical particle physics (T-8) groups, and became a Staff Member in 2007. I joined the University of Chicago faculty in 2011.


research summaries


multi-messenger astronomy


We have been exploring the ability of different networks of GW detectors to measure parameters of interest for binaries (such as the total mass and mass ratio, the distance, and the sky position), focusing on gamma-ray bursts as a particularly promising multi-messenger source (Dalal et al. 2006; Berger et al. 2007; Cutler & Holz 2009; Belczynski et al. 2010; Nissanke et al. 2010, 2011; Chen & Holz 2013, Belczynski et al. 2014). We have also used the rate of electromagnetic observations of gamma-ray bursts to predict the rate of binary mergers in advanced ground-based GW networks (Chen & Holz 2013). Because it is based directly on observations, this is arguably the most reliable estimate for the rate of GW events in the coming generation of ground-based detectors.


binary rates


We have worked extensively on estimating the rates of compact binary coalescences, both from a theoretical and an observational perspective (Berger et al. 2007; Belczynski et al. 2010a,b; Fryer et al. 2012; Belczynski et al. 2012; Dominik et al. 2012). These rates are critical to gravitational wave (GW) research, as binaries constitute the “bread and butter” sources for ground-based GW observatories: they are thought to occur often, are very loud in GWs, and can be detected from the ground. Highlights from our work include the potentially dramatic suggestion that advanced ground-based detectors (e.g., LIGO and Virgo) will measure a significantly higher binary black hole merger rate than that of binary neutron stars or neutron star–black hole systems (Belczynski et al. 2010). This is an important result, not only because it suggests that upcoming GW networks will detect many sources, but also because it highlights how GW observations probe the formation mechanisms of compact objects. We have also shown that by measuring the mass gap between neutron stars and black holes, GW observations will provide valuable empirical constraints on the supernova explosion mechanism (Belczynski et al. 2012, 2014a,b).


gravitational lensing


The Universe we find ourselves in is lumpy: there are tremendous matter overdensities (planets, stars, galaxies), and large areas devoid of matter (cosmic voids). The gravity from these inhomogeneities causes the light from distant objects to be deflected. This leads to changes in the images we see at Earth, a phenomenon known as gravitational lensing. I have worked extensively on lensing (Holz & Wald 1998; Holz 1998, 2001; Dalal et al. 2003; Holz & Linder 2005; Cooray et al. 2006a,b; Sarkar et al. 2008b; Joudaki et al. 2009; Cooray et al. 2010; Hirata et al. 2010), including exploring how lensing compromises the use of standard candles, or can be an important cosmological probe in its own right. I am currently focusing on the effects of lensing at high redshift, z>5 (Whalen et al. 2013, 2014).


other work


N-body simulations: I have been utilizing large cosmological simulations (run on supercomputers at Los Alamos) to study the formation and evolution of structure in the Universe (Warren et al. 2006; Wetzel et al. 2007, 2008; Tinker et al. 2008; Johnson et al. 2013, Skillman et al. 2014). This includes determining two of the canonical mass function of dark matter halos (for both friends-of-friends and spherical overdensity halos) and exploring “merger bias” (the impact of the merger history of a halo on its clustering properties).


massive clusters: In Holz & Perlmutter (2012) we made the first predictions for the mass and redshift of the single most massive cluster in the universe (M200 = 3.8 × 1015 M⊙ at z = 0.22, with 1σ marginalized regions 3.3 × 1015 M⊙ < M200 < 4.4 × 1015 M⊙ and 0.12 < z < 0.36). This calculation was based partially on my earlier work on dark matter halo mass functions (Warren et al. 2006; Tinker et al. 2008). There has subsequently been a great deal of activity on this topic, spurred by data from wide, deep, complete volume limited samples of galaxy clusters (e.g., from the South Pole Telescope). We are currently exploring the statistics of these massive clusters in detail, using an unprecedentedly large volume of simulation data (Skillman et al. 2014).


supernovae: I have been exploring the properties of supernovae, especially at high redshift (Holz 1998; Seljak & Holz 1999; Holz 2001; Fryer et al. 2002; Dalal et al. 2003; Fryer et al. 2004; Cooray et al. 2006a,b; Sullivan et al. 2007; Sarkar et al. 2008a,b; Cooray et al. 2010; Wang et al. 2012; Whalen et al. 2012, 2013a,b,c). Ongoing work is focusing on modeling the lightcurves of these early supernovae, and exploring the effects of gravitational lensing at the very high redshifts where they occur.


I’ve also proposed a particle dark matter candidate (Holz & Zee 2001), proposed a way to search for nearby black holes (Holz & Wheeler 2001), explored the radiation rocket effect (Favata, Hughes, & Holz 2004; Merritt et al. 2004), worked on dark energy (Li, Holz, & Cooray 2007; Sullivan, Cooray, & Holz 2007; Sarkar et al. 2008; Serra et al. 2009; Joudaki, Cooray, & Holz 2009; Cooray, Holz, & Caldwell 2010), as well as a number of other projects. See my papers for a full list.

Then felt I like some watcher of the skies

When a new planet swims into his ken;

Or like stout Cortez when with eagle eyes

He star'd at the Pacific--and all his men

Look'd at each other with a wild surmise--

Silent, upon a peak in Darien.


          John Keats

          On First Looking into Chapman's Homer

                    poem-chapman.html