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Hey, that’s me!

 

Welcome to my webpage, traveler.  Rest here, stay for a while.

I am the fifth year graduate student at the Department of Astronomy at the Ohio State University.

I have done work on a whole lot of things during my time here at (t)OSU!  Check me out on ADS to see all my papers.

 

 

I’ve recently submitted a paper examining 20 years of multi-wavelength variability of the nearby Active Galactic Nucleus (AGN) NGC 5273.  We especially concentrated the variability with respect to the exciting yet poorly understood “changing-look” phenomenon, where broad emission lines appear and/or disappear over the course of a few years.  While all AGNs are variable, this specific type of variability is extremely important in that it poses a direct challenge to the “unified model”, where the presence/absence of broad lines is thought to be a line-of-sight effect.  Moving back to NGC 5273, we report that the AGN changed-look at least once during the period from 2001 to 2022 (more tightly, between 2010 and 2014), and we claim that it may have done so multiple times based on its multi-wavelength variability.  However, due to lack of consistent spectroscopic observations, we cannot definitively say that the AGN changed-look more than once, though perhaps future observations will prove (or disprove!) our claim.   In any case, this study was a great experience and allowed me to personally handle data ranging from the near-infrared to hard X-rays, which is especially useful when AGNs emit at all these wavelengths.

 

Artist’s impression of an accretion disc surrounding a SMBH. Above the SMBH, an X-ray “lamppost” drives disc variability – or does it? Credit: NASA/JPL-Caltech.

My most recent published work has been on understanding the accretion disc variability in AGNs.  The current understanding of AGN discs includes an X-ray “lamppost” that sits above the disc and variably illuminates it.  This variable illumination causes the disc to vary in UV/optical wavelengths.  Our recent work attempts to map the disc itself using multi-filter AGN lightcurves, and we find that many of our maps are inconsistent with a lamppost-model.  Moreover, we find evidence that the disc may be driving its own variability, and perhaps even driving the lamppost itself.  See more here! 

 

Artist’s impression of a red supergiant dying as a failed supernova. A peculiar thing about the failed SN candidate that we found – it wasn’t a red supergiant – it was blue!  If proven to be a true failed SN, this could have tons of implications for our understanding of what kinds of stars die as failed SN.  Credits: NASA, ESA, and P. Jeffries.

I’ve also worked on stellar mass BHs with Professors Christopher Kochanek and Krzysztof Stanek on finding failed supernova (SN) candidates with the OSU-co-owned Large Binocular Telescope.  Failed SNe are what happen when stars are too massive to explode as SN and instead implode into BHs.  We reported the discovery of a new candidate failed SN and updated the failed SN fraction based on our observations.  Check it out!

 

 

Artist’s depiction of a TDE. ASASSN-18jd may have been one of these – or it may have been a very, very strange outburst of an AGN. Credit: NASA/JPL-Caltech

Going from stellar mass BHs back to SMBHs, I’ve also done work on Tidal Disruption Events (TDEs) detected by by the All Sky Automated Survey for SuperNova (ASAS-SN).  TDEs are the luminous flares that occur when a star gets ripped apart by the tidal forces of a SMBH and is accreted.  My first, first-author paper at OSU was characterizing ASASSN-18jd, a peculiar event that is not quite a TDE, and not quite an AGN.  At the time, ASASSN-18jd was unique in its peculiarity, but newer work has shown there to be a handful of ambiguous nuclear transients (ANTs) with similar in-between-TDE-and-AGN properties.

 

With all the different work I’ve done, you could say I’m a Jack of all trades!