E-mails from Breanna binder, UW grad student

Yes, Scott Anderson is my official faculty adviser, although the
majority of my research (and my thesis work) is being done with Ben
Williams. I study both AGN and X-ray binaries with X-ray and optical
data -- on the AGN side, I'm interested in low-luminosity AGN and
active intermediate-mass black holes. This year I won a Chandra
proposal to study the X-ray emission from about two dozen intermediate
mass black hole candidates, so that work will probably start next
quarter.

The bulk of my research is on XRBs in nearby galaxies. I'm not sure
how much you know about X-ray binaries, but I was a physics major too
so I came into grad school knowing very little about astronomy - so I
apologize if this is too elementary-school for you :) X-ray binaries
are systems where you have a neutron star or a black hole
gravitationally bound to a normal star. High mass XRBs have massive
stellar companions, which don't live for very long (~10 million
years), while low mass XRBs have stars more like the Sun or smaller,
and so live for billions of years.

To construct a logN-logS distribution, you basically just count up the
number of XRBs (N) brighter than a given luminosity (S). Bright
sources are rarer and younger in age than faint but numerous old
sources. By measuring the shape of the logN-logS distribution for a
galaxy, you can then say something about when the galaxy formed its
stars: for example, if the logN-logS distribution is dominated by
bright, high mass XRBs, then you know the galaxy has a significant
portion of very young stars, and so must be currently undergoing star
formation.

My thesis is taking Chandra X-ray data to study the XRBs, and
comparing it to optical Hubble Space Telescope data to study the
underlying stellar population.

I hope that wasn't too long winded! :)


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We find X-ray source candidates using a routine called wavdetect,
which is part of the Chandra Interactive Analysis of Observations
(CIAO) software. Once we've found a bunch of candidates, I run an IDL
program called ACIS_Extract to evaluate the source properties and the
probability that the source is real (and not some background flare or
detector noise).