Interested in carrying out research with my team? =>
Contact ME to discuss possibilities
AGN:
Super-massive black holes (SMBHs; >1e6 Msun) are now believed to
reside at the centers of nearly all massive galaxies. As such, the
cosmological evolution of AGNs and the growth of the SMBHs that
power them are extremely important constraints on models of galaxy
formation and evolution. Obtaining a true census of these AGN,
however, has proven difficult due to various observational
biases. Invariably, one must look to several different tracers such
as >2keV X-ray continuum, mid-IR continuum, radio
continuum/morphology, and high-ionization emission lines to
understand the true AGN population. I have worked on large number of
SMBH-related topics over the past ~20 years, from in-depth studies
of nearby AGN to surveys of many 100s to 1000s of distant AGN, using
some of the deepest
Chandra,
HST,
Spitzer, and ground-based observations ever performed.
Current works in progress:
- AGN variability and SED selection with current surveys (ZTF, LSQ, Legacy Survey, ...)
- Varibility characterization of AGN (BASS, IMBH candidates, ...)
- Study of AGN host morphologies (BASS)
- AGN Tracer correlations
- Improving the Positional Uncertainties of Chandra Sources
Future works ("in planning stages"):
- AGN selection and demography with LSST
- AGN spectral properties at z>1 with VLT-MOONS
- AGN spectral properties with 4MOST
Galaxy Evolution:
Deep surveys have demonstrated that bright IR-selected dusty
star-forming galaxies (DSFGs) trace a distinctly disjoint channel of
obscured star formation from UV-selected galaxies. Both UV and IR
samples need to be assessed to understand their relative contributions
to cosmic star formation history. One of the most fundamental
questions is how and why these different modes of star formation
exist. For the past few years, I have been working on studies to find
and characterize obscured and unobscured galaxies at high redshift.
Current works in progress:
- Multi-wavelength constraints (ALMA, MUSE, NIR-spectra) on emission-line galaxies and DSFGs behind lensed clusters and in blank-field surveys
- ALMA and NIR observations of high-redshift (z>6) galaxies
Transients and Supernovae:
I began studying ultraluminous X-ray sources (ULXs) and supernovae
(SNe) through the serendipitous detection of ULXs such as CG X-2 and SN1996cr
wth
Chandra in 2000 June (Sambruna et al. 2001, Bauer et
al. 2001).
I eventually confirmed SN1996cr as a
type IIn SN in 2006 using VLT spectroscopy (Bauer et al. 2007;
2008). SN1996cr showed several parallels with the peculiar SN
1987A (albeit >1000 times more luminous!), as well as nearby SN
1978K and SN 1979C. The archival X-ray and radio lightcurves and
spectra for SN 1996cr indicated that a compact, dense
shell was formed by the progenitor due to a dramatic stellar
wind changes as little as 100 yrs prior to the SN, which created a
wind-blown bubble; this rapid evolution is intriguing and
must be reconciled against theoretical stellar evolution models. I
have initiated wide-ranging follow-up observations of SN1996cr (see
below).
SN1996cr and CG X-2 piqued my interest in transients more generally,
and I am currently involved in follow-up programs to
place constraints on these intriguing objects in conjunction
with both the
Millenium Institute of
Astrophysics group and several international
collaborations. I list below ongoing/proposed projects:
- Transients discovery and classification via ALERCE broker for ZTF, ATLAS, LSST, etc.
- Multi-wavelength follow-up of transients (including Gravitational Wave events)
- Searches for and characterizations of fast X-ray transients
- Expanding strong multi-wavelength constraints to other nearby SNe
- Radio/mm/IR evolution of SN1996cr
Galactic Center:
I am involved in a several projects to study high- and low-mass X-ray binaries (HMXBs, LMXBs)
in the inner 300 pc region of the Galactic Center using X-ray surveys.
The goals of this study are to test various models for
the Galactic Center star formation history, constrain the origin
and fate of hot, X-ray emitting plasma that suffuses the region,
and assemble a large sample of quiescent HMXBs for spectroscopic
follow-up. Pinning down the positions of the best candidates is
critical in order to facilitate meaningful multi-wavelength follow-up studies for the
various underlying source populations, including the HMXBs.
The lack of deep, high spatial resolution K-band imaging has been a major limitation
to this point.
Current projects:
- Identification of candidate BHs in the Galactic Center and Spectroscopic follow-up
RBSC-NVSS Cross-Correlation:
For my PhD thesis (along with Jim Condon, Trinh Thuan, and John Broderick), I cross-identified the ROSAT All Sky Survey Bright Source Catalogue (RBSC; Voges et al. 1998) with the NRAO VLA Sky Survey (NVSS; Condon et al. 1998) and the USNO optical catalogue (USNO; Monet et al. 1999) to produce a well-defined sample of 1556 IDs for multi-wavelength studies. Here is a link to the full thesis in all its beastly glory (and
ADS reference in case you wish to cite something from it). Here are the relevant chapters:
- RBSC-NVSS I: Sample definition and ID methodology (ps)
Table 1 (ps, txt) - RBSC-NVSS stellar objects (44)
Table 2 (ps, txt) - RBSC-NVSS extragalactic objects (1512)
- RBSC-NVSS II: Optical Spectroscopic properties - unpublished (sigh)
Spectra Data (tgz) - ascii spectra, fit parameters, and plots of resulting fits
- RBSC-NVSS III: Multiwavelength properties, Analysis, Luminosity
Functions, etc. - unpublished and largely outdated now (sigh)