Latest news in our group
Hsiang-Chih Hwang receives the Gardner Fellowship. Many congratulations!!
Another batch of recently submitted papers:
Dempsey and Zakamska conduct a theoretical investigation of the size-luminosity relationship of quasars' narrow emission line regions. We find that in order to produce the ~10 kpc photo-ionized nebulae around powerful quasars, line-emitting clouds must be ionization-bounded, which means that emission-line regions contain 3-30 times more gas than is detectable via the emission lines.
Lambrides et al. present the largest study of molecular gas and polycyclic aromatic hydrocarbons using Spitzer spectra, finding that the excitation temperatures of the warm molecular gas are high in galaxies with active nuclei than without, a potential signature of feedback activity.
Goulding, Zakamska et al. present an X-ray study of extremely red quasars at high redshift. These objects are among the most highly X-ray obscured quasar populations, yet they are intrinsically luminous in X-ray.
Our group's proposal for Early Release Science with the James Webb Space Telescope was approved! Many congratulations to Principal Investigator Dr. Dominika Wylezalek!
Here are some of the papers submitted by our group members in the last few months:
Alexandroff R.M., Zakamska, N.L., et al. in the paper "Spectropolarimetry of high redshift obscured and red quasars" find fascinating spectropolarimetric signatures of equatorial outflows in extremely powerful quasars at the peak epoch of galaxy formation.
Wylezalek, D., Zakamska, N.L., et al. develop new methods of "Identification of active galactic nuclei in optical integral field unit surveys" and find that the standard diagnostic diagrams used for distinsguishing star-forming regions from active galactic nuclei based on single-fiber and nuclear spectroscopy need to be re-thought for extended ionized gas regions.
Hwang H.-C., Zakamska N.L. et al. discuss "Winds as the origin of radio emission in z=2.5 radio-quiet extremely red quasars" and find that low- and high-redshift obscured and red quasars form one relationship between the kinematics of ionized gas and radio luminosity among the radio-quiet quasars. This is an important clue about the origin of the radio emission in radio-quiet quasars which is not yet well understood.
Qin W., Nataf D., Zakamska N.L. et al. investigate a large sample of Mira-type variables in "Mira-based distance to the Galactic Center" and improve the understanding of extinction and metallicity corrections, making Miras more competitive as distance indicators.
Our department is now accepting applications for the Ph.D. program, with a starting date of August 2018, as described here. Our graduate program allows and encourages research rotations. Therefore, prospective students are welcome to indicate in the application that they are interested in joining our group; however, no detailed research proposal is required at this stage, and the admissions committee is more interested in past experiences and accomplishments in research and academics. Example student papers produced by our group are posted throughout this website, and prospective graduate students will have many opportunities to learn about specific projects that will be available in our group in Fall of 2018 after the admission decisions are made in winter 2018 and before committing to our program.
Undergraduate research interns Anthony Flores, Wenzer Qin and Channa Luke present at the Maryland Space Grant research symposium. Wenzer wins a 2nd place in the "Best speaker" competition! More information here.
Congratulations to Dr. Rachael Alexandroff on a successful Ph.D. defense! Dr. Alexandroff will be moving to the University of Toronto as a Canadian National Research Fellow in Fall 2017.
Welcome to summer interns -- Suri, Anthony, Wenzer and Channa -- with many thanks to the Maryland Space Grant for the funding opportunities!
Postdoctoral supervisors are Dr. Kate Rowlands, Dr. Dominika Wylezalek, and Dr. David Nataf:
4th Annual Quasar Day (JHU/Drexel/Princeton)
Here is the schedule
Asa Stahl receives Provost's Undergraduate Research Award -- many congratulations! Previous recipients of PURA and DURA (Dean's Award) in our group include Michael Kelly, Kelly Lampayan, Georges Obied and Matthew Hill.
A press release on the discovery of a population of extremely red quasars with powerful outflows, related to the recent paper by Hamann, Zakamska et al. and the previous paper by Zakamska, Hamann et al. Many thanks to collaborator Fred Hamann at UC Riverside for spear-heading the press release.
Prospective graduate students wishing to start in September 2017 can apply as described here. We have lots of new content on the graduate program website, including profiles of recent alumni, graduation stats, and description of the program structure. Prospective students are welcome to indicate in the application that they are interested in joining our group; however, no detailed research proposal is required at this stage, and the admissions committee is more interested in past experiences and accomplishments.
Wylezalek, Schnorr Muller, Zakamska et al. (submitted to MNRAS) use Gemini GMOS intrument to zoom into the centers of nearby active galaxies studied with MaNGA integral field spectroscopic survey, to find strong nuclear outflows likely driven by black hole activity.
Hamann, Zakamska, Ross et al. (accepted to MNRAS) present a population of very intriguing high-redshift red quasars which may be linked to the strong outflow phase of galaxy evolution.
A paper led by Dominika Wylezalek finds observational evidence that specific star formation is suppressed in hosts of quasars with fastest outflows. This could be the long-sought sign of "negative" quasar feedback postulated in galaxy formation theory.
I was very pleased to see my Special Relativity textbook listed in "The Net Advance of Physics" Special Relativity library.
Nadia Zakamska receives Catalyst Award from Johns Hopkins University.
Dr. Dominika Wylezalek has been awarded the Provost's Postdoctoral Fellowship -- congratulations!
The largest catalog of type 2 quasars by Yuan, Strauss and Zakamska with lots of ancillary data is now publicly available here and the paper describing the catalog has been submitted to MNRAS. We are also releasing all [OIII] kinematics from the previous largest catalog by Reyes et al. 2008, Zakamska and Greene 2014.
News from the Department's Award Ceremony: Rachael Alexandroff receives the E.J.Rhee Travel Award and Joseph Cleary receives the Donald E. Kerr Memorial Prize -- congratulations!
Michael Kelly successfully presents his Master's thesis on active galactic nuclei in MaNGA data and will be receiving a Master's degree!
Alexandroff et al. 2016 -- a sensitive radio survey of obscured quasar candidates finds that radio emission in radio quiet quasars is extended on a few kpc scales and that it has steep spectral indices; this observation may be a critical clue in understanding the nature of the radio emission of radio-quiet quasars. Submitted to MNRAS.
Press release on our work on Sunyaev-Zeldovich effect from quasar feedback. Here is the original JHU version.
The video of the public discussion of LIGO results at the Institute for Advanced Study, moderated by Director Robbert Dijkgraaf, with panelists Matias Zaldarriaga, Scott Tremaine, Nadia Zakamska and Doron Kushnir.
Wylezalek et al. 2016 -- a joint study of quasar hosts and their winds with HST and Gemini -- now in press in MNRAS.
Guilin Liu, a former postdoc in our group, will be moving to a faculty position at the University of Science and Technology in China in Fall 2016. Many congratulations!
Obied et al. 2015 -- detection of giant scattering cones in obscured quasars using the HST data and the implications for the unification model of active galaxies -- now in press in MNRAS.
Zakamska et al. 2015, Discovery of extreme [OIII]5007A outflows in high-redshift red quasars -- quasar-driven outflows proceeding at several thousand km/sec, likely on the scales of the host galaxy, submitted to MNRAS
The textbook "Theory of Special Relativity" by N.L.Zakamska is now publicly available.
Stern et al. 2015, Constraining the dynamical importance of hot gas and radiation pressure in quasar outflows using emission line ratios, submitted to ApJ
Evidence for the Thermal Sunyaev-Zel'dovich Effect Associated with Quasar Feedback -- our novel view of quasar feedback in the paper by Devin Crichton et al. 2015
The Department of Physics and Astronomy at Johns Hopkins University is planning to offer a Davis Postdoctoral Fellowship in Astrophysics this year. The position will start in September 2016.
Prospective graduate students wishing to start in September 2016 can apply as described here.
Some papers our group submitted in the last couple of months include:
Towards a comprehensive picture of powerful quasars, their host galaxies and quasar winds at z=0.5 (Wylezalek et al. 2015),
Giant scattering cones in obscured quasars (Obied et al. 2015),
Star formation in quasar hosts and the origin of radio emission in radio-quiet quasars (Zakamska et al. 2015)
Dr. Dominika Wylezalek becomes inaugural Akbari-Mack Fellow! Congratulations to Dominika, and many thanks to Dr. Akbari and Mr. Mack for their support!
Kelly Lampayan and Georges Obied, both undergraduate researchers in Zakamska research group, share the Donald E. Kerr Memorial Award for outstanding Physics majors. Furthermore, Georges Obied qualifies for the M.A. degree! Prasenjit Bose receives Rowland Prize for innovation and excellence in teaching for outstanding work as teaching assistant in Special Relativity / Waves by Zakamska, following several years of excellence in teaching courses for non-majors. Prasenjit continues the streak of awards to teaching assistants for Special Relativity / Waves, following Edwin Chan (teaching award in May 2013) and Anirban Ghosh (teaching award in May 2014). Congratulations!
Prospective graduate students wishing to start in September 2015 can apply as described here. Here is our flyer, and this is some general information regarding our astrophysics graduate program.
"Nadia L. Zakamska wins the 2014 Newton Lacy Pierce Prize of the American Astronomical Society"
Pictures from the award ceremony, June 2014
JHU press release,
The materials for the IAS public lecture are posted here.