Here I list some current and past projects, with the most relevant publications for each of them. If you have questions please email me.
The Sloan Digital Sky Survey has collected millions of spectra of individual objects, from quasars to galaxies and stars. Most of these spectra have multiple visits, and it is possible to study them to look for variations in radial velocity (RV) due to the presence of an unseen binary companion. I have been involved in several efforts to use these data to improve our knowledge of stellar multiplicity.
White Dwarfs: These degenerate stars are very dense and small - a typical white dwarf is roughly the size of planet Earth. As a consequence, they can be in binary systems with very short periods, sometimes only a few minutes. These short period binary white dwarfs are very interesting because they can be the progenitors of Type Ia supernovae. In 2009, we used time-domain SDSS spectra to discover some of these systems (Badenes et al. 2009, Mullally et al. 2009). In 2012, we took these studies one step further, using the statistical properties of thousands of individual radial velocities measured by SDSS (Maoz et al. 2012) to constrain the merger rate of binary white dwarfs in the Milky Way (Badenes & Maoz 2012, see the NSF Press Release). We have recently revised this measurement with new data, concluding that binary white dwarfs merge at a very high rate (Maoz et al. 2018)
Main sequence stars and Red Giants: Thanks to the unprecedented spectral resolution of the APOGEE IR spectrographs in SDSS, we have been able to conduct a systematic exploration of the fundamental statistics of stellar multiplicity and their dependance on stellar properties, from the Main Sequence to the Horizontal Branch. We found that there is a very strong anti-correlation between stellar metallicity and the fraction of stars with close companions (periods of a few years or less). See Badenes et al. 2018 and Moe, Kratter, and Badenes 2019.
Follow-up of interesting systems: Coming soon.
NEWS: I am proud to announce that I have become an Associate Member of the fifth installment of SDSS, SDSS-V, scheduled to begin operations in 2020. This continues the historical involvement of Pitt in SDSS, which started back in 2003. SDSS-V will revolutionize our knowledge of the stellar content of the Milky Way, so stay tuned for developments!
Supernova Remnants are the end products of Supernova explosions. Observations of SNRs in the Local Group offer a unique view of Supernovae, complementary to optical studies of distant objects.
Models for the X-ray Spectra of Type Ia SNRs: Back in 2004, I wrote a PhD thesis on this topic, which you can download here (though most of it is now outdated). In a nutshell, the X-ray spectra of Type Ia SNRs contain a lot of information about the physics of the explosion and the structure of the medium surrounding the progenitor, which are in turn crucial to understand the nature of SN Ia progenitors (see Badenes 2010 for a short review on this topic).
Neutronization in Type Ia SNRs:
SNR Populations in the Local Group:
If you are interested in any of these research projects, I would be happy to talk to you. If you want to work with me as a graduate student, keep in mind that first you need to be admitted into our Graduate Program. You can find detailed instructions on how to apply here.
This research is supported by grants from NASA, NSF and the Research Corporation.