Astrophysics Science Division Colloquium Series
Schedule: Spring 2016

Astrophysics Science Division Colloquium Series
Schedule: Spring 2016

Recent schedules:

  2016, Spring  
2015, Fall 2015, Spring  
2014, Fall 2014, Spring  
2013, Fall 2013, Spring 2013, Summer
2012, Fall 2012, Spring  
2011, Fall 2011, Spring  
2010, Fall 2010, Spring  

ASD Colloquia are Tuesdays at 3:45 pm (Meet the Speaker at 3:30 pm)
in Bldg 34, Room W150 unless otherwise noted.

January

Jan 5 No Colloqium (AAS Meeting)
Jan 12 Francesco Tombesi (UMD) - How Can Supermassive Black Holes Drive the Evolution of Entire Galaxies?
Jan 19 No Colloquium (MLK day)
Jan 26 Cancelled (snow)

February

Feb 2 Manfred Cuntz (U. Texas at Arlington) - Habitability Around Single Stars and in Multiple Stellar Systems
Feb 9 Keivan Stassun (Vanderbilt) - Advances in Stellar Astrophysics, Star Formation, and Exoplanet Science with Large Surveys
Feb 16 No Colloquium (President's Day)
Feb 19 Special Date
Jordan Camp (GSFC) - Detection of Gravitational Radiation from a Merging Black Hole Binary and the New Era of Gravitational Wave Astronomy
Feb 23 Nico Cappelluti (Yale) - Search for signatures of early black holes

March

Mar 1 Brian McNamara (Waterloo) - Molecular Gas Flows in Cluster Cores Revealed by ALMA
Mar 8 Special Location: B34, W120 A&B
Tracy Slatyer (MIT) - Indirect Dark Matter Searches (tentative title)
Mar 15 Special Location: B34, W120 A&B
Nick Cowan (McGill) - Super-Earths (tentative title)
Mar 22 Kaya Mori (Columbia) - Galactic Center with NuSTAR (tentative title)
Mar 29 Ewine Van Dishoeck (Leiden) - Astrochemistry (tentative title) (Goddard Science Colloquium / Bahcall Lecture)

April

Apr 5 (TBC) Daniel Kocevski (GSFC) - Time Domain with Fermi (tentative title)
Apr 12 Francesco Miniati (Zurich) - High-resolution Simulations of Turbulence in Galaxy Clusters (tentative title)
Apr 19 Maria Petropoulou (Purdue) - High-energy Signatures (Photons, Neutrinos) from Blazars (tentative title)
Apr 26 Special Time: TBD
Dominik Riechers (Cornell) - Cold Gas in High-z Galaxies with VLA and ALMA (tentative title)

May

May 3 Tiziana Di Matteo (CMU) - The Next Frontier of High-redshift Quasars and Massive Galaxies
May 10 Lou Strolger (STScI) - Cosmology with Supernovae (tentative title)
May 17 Special Location: B34, W120 A&B
Shane Larson (NW) - Gravitational Waves (tentative title)
May 24 Cora Dvorkin (Harvard) - Observational Cosmology and Fundamental Physics (tentative title)
May 31 No Colloquium (Memorial day)

June

Jun 7 James Reeves (Keele) - X-ray Spectroscopy of AGN (tentative title)
Jun 14 John Silverman (Tokyo) - Subaru Deep Surveys (tentative title)

How Can Supermassive Black Holes Drive the Evolution of Entire Galaxies?

Francesco Tombesi

UMD

Tuesday, Jan 12, 2016

Abstract

Powerful winds driven by active galactic nuclei (AGN) are often invoked to play a fundamental role in the evolution of both supermassive black holes (SMBHs) and their host galaxies, quenching star formation and explaining the tight SMBH-galaxy relations. A strong support of this "quasar mode" feedback came from the recent X-ray observation of a mildly relativistic accretion disk wind in an ultraluminous infrared galaxy and its connection with a large-scale molecular outflow, providing a direct link between the SMBH and the gas out of which stars form. Spectroscopic observations, especially in the X-ray band, show that such accretion disk winds may be common in local AGN and quasars. However, their origin and characteristics are still not fully understood. Detailed theoretical models and simulations focused on radiation, magnetohydrodynamic (MHD) or a combination of these two processes to investigate the possible acceleration mechanisms and dynamics of these winds. Some of these models have been directly compared to X-ray spectra, providing important insights into the wind physics. However, fundamental improvements on these studies will come only from the unprecedented energy resolution and sensitivity of the upcoming missions ASTRO-H (launch date early 2016) and Athena (2028).

Habitability Around Single Stars and in Multiple Stellar Systems

Manfred Cuntz

U. Texas at Arlington

Tuesday, Feb 2, 2016

Abstract

Habitability, i.e., the planet’s potential to develop and sustain life, is a topic of intense research, encompassing both favorable conditions as, e.g., the size and stability of the stellar climatological habitable zones as well as adverse forcings. The latter encompass numerous factors including (but not limited to) intense UV, X-rays, and flares, including superflares, which have the potential of evaporating planetary atmospheres. These constituents apply to both planets around single stars and those hosted by multiple stellar systems. Regarding the latter, the analysis of planetary habitability is, however, more complex as, e.g., the presence of multiple stellar components affects both the extent and time-dependence of the climatological habitable zones and the domains of planetary orbital stability. Recent progress has been made in regard to binary systems, pertaining to both S-type and P-type planetary orbits. Detailed results have been obtained for a large variety of observed and theoretical systems, including systems detected by the Kepler mission. The purpose of my talk is to summarize recent results and to convey perspectives of future research.

Advances in Stellar Astrophysics, Star Formation, and Exoplanet Science with Large Surveys

Keivan Stassun

Vanderbilt

Tuesday, Feb 9, 2016

Abstract

Large surveys, such as the Sloan Digital Sky Survey and the upcoming Large Synoptic Survey Telescope, are revolutionizing many areas of astrophysics. I present some recent discoveries that highlight the diversity of advances enabled by large surveys of stars and exoplanet systems, including: (1) that the most and least tightly bound binary star systems likely have a common dynamical origin; (2) that the properties of low-mass stars and of benchmark eclipsing binary systems can be corrupted through the effects of magnetic activity and of tertiary bodies; and (3) that the "flickering" of stars, due to the granulation of their surfaces, reveals the true physical properties of exoplanets. I close with some thoughts on the role of human visualization for discovery with big data.

Detection of Gravitational Radiation from a Merging Black Hole Binary and the New Era of Gravitational Wave Astronomy

Jordan Camp

GSFC

Friday, Feb 19, 2016

Abstract

The era of Gravitational Wave Astronomy has begun. On Sept 14 2015 the Laser Interferometer Gravitational Wave Observatory (LIGO) detected gravitational radiation from the last moments of the merging of a Black Hole Binary system. I will describe the detection and its implications, as well as the incredible sensitivity of the LIGO detectors that made the detection possible. I will give some background on the notion of Black Holes since they were first predicted as a consequence of Einstein's theory of General Relativity in 1916. Finally, I will talk about Goddard's role going forward in this highly promising new field of astronomy.

Search for signatures of early black holes

Nico Cappelluti

Yale

Tuesday, Feb 23, 2016

Abstract

Search for the formation mechanism of supermassive black holes (SMBH) requires to access, with X-ray observations, the Universe at z>5. This is a challenge, because the deepest Chandra observations, combined with HST-WFC3, provide only a handful of candidate high-z AGNs that can be used to test the SMBH formation machanisms. Beyond that, we need to search for their footprints in the cosmic backgrounds. I will present recent observational result that may shed light on the first black holes in the Universe. In particular, recently detected joint fluctuations of the Chandra Cosmic X-ray Background and the Spitzer Cosmic Infrared Background are opening a new window on this epoch of the cosmic history and paving the way for JWST, The X-ray Surveyor and Athena.

Molecular Gas Flows in Cluster Cores Revealed by ALMA

Brian McNamara

Waterloo

Tuesday, Mar 1, 2016

Abstract

Dozens of brightest cluster elliptical galaxies contain molecular gas reservoirs exceeding 10^9 solar masses, fuelling star formation rates of tens of solar masses per year. These galaxies are embedded in hot, X-ray atmospheres where the cooling time falls below one Gyr. The cooling atmospheres are expected to form molecular clouds that fuel star formation and energetic feedback from central supermassive black holes. New observations of a half dozen brightest cluster galaxies obtained with the Atacama Large Millimeter Array are revealing a diversity of molecular gas dynamics and morphologies including, molecular inflow, outflow, and star formation occurring preferentially in filaments rather than in molecular disks. Molecular cloud ensemble velocities generally lie far below the stellar velocity dispersions, indicating their motions are not governed by gravity. I will show that AGN feedback scales with halo mass, and I will suggest that molecular gas fuelling feedback likely cooled in the wakes of buoyantly-rising radio bubbles.

The Next Frontier of High-redshift Quasars and Massive Galaxies

Tiziana Di Matteo

CMU

Tuesday, May 3, 2016

Abstract

I will discuss predictions for the first quasars and the first galaxies and their contribution to reionization from the BlueTides simulation. BlueTides is a uniquely large volume and high resolution simulation to study the high redshift universe: with 0.7 trillion particles in a volume of 1/2 of a Gigaparsec on the side. This is the first simulation large enough to resolve the relevant scales that form the first massive galaxies and quasars. These massive objects at high redshifts will be the next frontier for the next generation telescopes (Euclid, JWST, WFIRST).


Maxim Markevitch
NASA Logo, National Aeronautics and Space Administration