Bulletin of the American Physical Society
Annual Meeting of the Four Corners Section of the APS
Volume 57, Number 11
Friday–Saturday, October 26–27, 2012; Socorro, New Mexico
Session C2: Active Galactic Nuclei in Galaxies |
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Chair: David Meier, New Mexico Institute of Mining and Technology Room: Macey Center Auditorium |
Friday, October 26, 2012 1:15PM - 1:39PM |
C2.00001: New Insights into Galaxy Evolution: the Atlas3D project Invited Speaker: Lisa Young Nearby galaxies have preserved the records of their formation and evolution in the details of their structures, stellar populations, and gas contents. Drawing on the work of the Atlas3D team, I will review some recent insights into the evolution of early-type (elliptical and lenticular) galaxies. For example, observations of the stellar kinematics are coupled with numerical simulations to understand what kinds of galaxy mergers have built up the galaxies we see today. Stellar populations can be used to read the star formation histories of the galaxies, and observations of the cold gas contents of early-type galaxies also reveal their interactions with their environments. [Preview Abstract] |
Friday, October 26, 2012 1:39PM - 1:51PM |
C2.00002: The Intermediate-Mass Black Hole Candidate in the Center of NGC 404 Kristina Nyland, Josh Marvil, Joan M. Wrobel, Lisa M. Young, B. Ashley Zauderer We present the results of deep, high-resolution, 5 GHz Expanded Very Large Array (EVLA) observations of the nearby, dwarf lenticular galaxy and intermediate mass black hole candidate ($M_{\mathrm{BH}}$ $\sim$4.5 $\times$ 10$^5$ M$_{\odot}$), NGC 404. We found a modestly resolved source in the NGC 404 nucleus with a total radio luminosity of 7.6 $\pm$ 0.7 $\times$ 10$^{17}$ W Hz$^{-1}$ at 5 GHz and a spectral index from 5 to 7.45 GHz of $\alpha$ = $-$0.88 $\pm$ 0.30. NGC 404 is only the third central intermediate mass black hole candidate detected in the radio regime with subarcsecond resolution. The position of the radio source is consistent with the optical center of the galaxy and the location of a known, hard X-ray point source ($L_{\mathrm{X}}$ $\sim$ 1.2 $\times$ 10$^{37}$ erg s$^{-1}$). The faint radio and X-ray emission could conceivably be produced by an X-ray binary, star formation, a supernova remnant or a low-luminosity AGN powered by an intermediate mass black hole. In light of our new EVLA observations, we find that the most likely scenario is an accreting intermediate mass black hole, with other explanations incompatible with the observed X-ray and/or radio luminosities or statistically unlikely. [Preview Abstract] |
Friday, October 26, 2012 1:51PM - 2:03PM |
C2.00003: Photometric Reverberation Mapping of Mrk 926 Carla June Carroll, Michael Joner We have observed over 25 nights of the active galactic nuclei (AGN) Mrk 926 using the 0.9 m telescope from Brigham Young University's West Mountain Observatory (WMO) to determine the black hole mass through broad band photometric reverberation mapping (RM). Mrk 926 was chosen due to its strong emission lines and strong variability. Observations in the V and R band filters provided access to time variations in H$\beta$ and H$\alpha$ (respectively) as well as continuum. The I band filter provided exclusive continuum. Using similar techniques, Edri et. al. (2012) determined the black hole mass for the low-luminosity AGN NGC 4395, using continuous monitoring over several nights. We observed several more nights without needing continuous monitoring, allowing us to propose a refined black hole mass estimate from the time lag in H$\alpha$ for Mrk 926. [Preview Abstract] |
Friday, October 26, 2012 2:03PM - 2:15PM |
C2.00004: A Three-decade X-band VLBI Study of the Nucleus in the Lobe-dominated Quasar 3C207 David Hough We report on X-band (8.4/10.7 GHz) VLBI observations of the nucleus in the lobe-dominated quasar 3C207 from 1981 to 2010, mostly obtained with the NRAO VLBA. The goal is to follow flux outbursts and to fully determine the jet morphology and kinematics on 1-100 pc scales. Core region outbursts occur at mean intervals of 7 yr. The core region is resolved, and can be modeled with a stationary true core and a swinging component separated by about 0.5 mas. This reveals that two of the apparently single core region outbursts are actually double outbursts in the true core. The swinging component has varied in position angle (PA) over a range of 40 degrees, with jet components emerging along paths spread over 25 degrees. Numerous jet components are detected out to 25 mas. Average superluminal speeds are about 10c. One component has been seen to undergo an apparent acceleration from 7c to 14c at about 2-3 mas from the true core, in what we identify as a jet recollimation zone that appears to redirect the flow along an average PA of about 90 degrees. We detect definite expansion of individual jet components until they reach the recollimation zone. Possible physical interpretations will be discussed. [Preview Abstract] |
Friday, October 26, 2012 2:15PM - 2:27PM |
C2.00005: An Experiment to Demonstrate an $\alpha\omega$ Dynamo in the Accretion Disk leading to Galaxy and MBH formation Jiahe Si, Stirling Colgate, Hui Li, Vladimir Pariev, David Westpfahl, Joe Martinic The largest concentrations of free energy in the universe are the radio lobes associated with the central galactic black hole formation, in form of magnetic energy, $\sim 10^{62}$ ergs of $B^2/8\pi$, $\sim$10\% of MBH $c^2$. It's generally believed that the magnetic fields are amplified from very weak seed fields by the interaction of electrically conducting fluid motion, the so-called dynamo mechanism. Turbulence inhibits a dynamo, which must have coherence and phase information (Cattaneo and Tobias) in Baryon-dominated hydrodynamics. We are attempting an experiment to demonstrate an $\alpha\omega$ dynamo in New Mexico Institute of Mining and Technology with liquid sodium in limiting stable Couette flow between two co-rotating cylinders, $\Omega_1=17.5$Hz and $\Omega_2=70$Hz, 60cm and 30cm in diameter. The Helicity is produced by driven plumes analogous to star-disk collisions in the astrophysical limit. Including signals from 18 Hall detectors, 5 pressure and 5 temperature sensors in rotating frame, 2 rotation speed, 2 current, 2 torque sensors, and other sensors in stationary to monitor the experimental apparatus operation, there are more than 45 signals must be digitized and transmitted in serial, and finally decoded in data acquisition computer to characterize the experiment. [Preview Abstract] |
Friday, October 26, 2012 2:27PM - 2:51PM |
C2.00006: An Experiment to Demonstrate the $\alpha-\Omega$ Dynamo in the Accretion Disk Leading to Galaxy and Massive Black Hole Formation Invited Speaker: Stirling Colgate The largest concentrations of free energy in the universe are the radio lobes associated with the central galactic black hole formation, about $10^{62}$ ergs of $B^2/8\pi$, or about 10$\%$ of $M_{bh} c^2$. How do we get to a $10^8$ solar mass black hole and a flat rotation curve galaxy with a massive black hole at its exact rotation center and put the free energy in the magnetic field? This may mean that about $10^5$ solar masses of low energy (a few Mev) neutrinos are emitted in the process. Could we detect them with Gadzooks? How do baryons do this in a dark matter potential? Turbulence inhibits a dynamo, which must have coherence and phase information (Cattaneo and Tobias) in baryon-dominated hydrodynamics. The proof is in an experiment. [Preview Abstract] |
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