Bulletin of the American Physical Society
2012 Annual Meeting of the California-Nevada Section of the APS
Volume 57, Number 13
Friday–Saturday, November 2–3, 2012; San Luis Obispo, California
Session H1: Astrophysics |
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Chair: Virginia Trimble, University of California, Irvine Room: Business 003 0205 |
Saturday, November 3, 2012 2:00PM - 2:12PM |
H1.00001: Disappearing Broad lines in Active Galaxies? Bryan Scott, Vardha Bennert, Tommaso Treu, Matthew Auger, Stefanie Komossa Active galactic nuclei (AGN) are among the most luminous objects in the universe, and consequently can be studied at large distances. It is therefore of importance to understand both the mechanism and potential time variation of the behavior of these objects. Broad emission lines in spectra from these objects can be used to measure the mass of the supermassive black hole believed to lie at the heart of these galaxies. A sample of approximately 100 AGN in the local universe were observed using the Keck I telescope in order to to estimate black hole masses and to measure stellar velocity dispersions. Of these objects in the survey, all of which had previously been classified according to the characteristic presence of broad emission lines as type I AGN from Sloan Digital Sky Survey spectra, six surprisingly seem to lack broad emission lines in the Keck spectra taken a few years later. We present analysis of the Keck and SDSS spectra and discuss possible implications for our understanding how AGN spectra vary with time, and consequently, the mechanism underlying AGN emission. [Preview Abstract] |
Saturday, November 3, 2012 2:12PM - 2:24PM |
H1.00002: Determining Stellar Velocity Dispersion in Active Galaxies: Is the [OIII] Width a Valid Surrogate? Kelsi Flatland, Vardha N. Bennert, Matthew W. Auger, Tommaso Treu The tight empirical relation between the stellar velocity dispersion ($\sigma$) of the bulge and the mass of the supermassive black hole (BH) at its center indicates a close connection between galactic evolution and BH growth. The evolution of this relation with cosmic time provides valuable clues to its origin. While the mass of the BH can be easily estimated using the Doppler broadening of the H$\beta$ emission line in type-1 active galactic nuclei (AGNs), measuring $\sigma$ simultaneously is challenging, since the nuclear emission outshines the host galaxy. Thus, it is highly desirable to find an alternative way to estimate $\sigma$. In the literature, the width of the [OIII] emission line has been used as a surrogate, assuming that the narrow-line region follows the gravitational potential of the bulge. While the [OIII] line has the great advantage of being easily measurable in AGNs out to large redshifts, it is also known to be affected by outflows and jets. For a sample of about 100 nearby active galaxies, we determine the width of the [OIII] line using two Gaussians to exclude any outflowing component. The resulting width is compared to $\sigma$ measurements previously compiled from Keck spectroscopy for the entire sample to determine the method's viability. [Preview Abstract] |
Saturday, November 3, 2012 2:24PM - 2:36PM |
H1.00003: The Outbursts of the Cataclysmic Variable V425 Cassiopeiae Dillon Trelawny, Fred Ringwald We report time-resolved photometry of the cataclysmic variable V425 Cassiopeiae, taken over several weeks in 2010, 2011, and 2012 at Fresno State's station at Sierra Remote Observatories. We measure a long-term period of 4.24 $\pm$ 0.71 days and a 1.0 magnitude amplitude. This is separate from the orbital period of 0.1496 days (Shafter 1983). Our period value is in direct contrast with a period measured by Kato et al. (2001) of 2.65 days for the same system. As a result of this long-term variability, Kato et al. proposed that V425 Cas is a VY Scl-type system, which is characterized by periods of high mass transfer rate and periods of very low mass transfer rates. We argue that, based on our extended observations, V425 Cas is instead a Z Cam-type system, characterized by standstills, between dwarf nova outbursts that recur rapidly. Observations from Kato et al. (2001) are included for comparison.~ Further evidence of near-infrared magnitudes of V425 Cas from the 2MASS survey and its absolute magnitudes at outburst maximum, standstill, and minimum are included to support our argument. [Preview Abstract] |
Saturday, November 3, 2012 2:36PM - 2:48PM |
H1.00004: Searching for Q-Balls with the High Altitude Water Cherenkov Observatory Peter Karn The High Altitude Water Cherenkov (HAWC) experiment is a gamma-ray observatory currently under construction at Sierra Negra in Mexico. When complete it will consist of a 20,000 square meter array of 300 water Cherenkov detectors, each with 50,000 gallons of water and four photomultiplier tubes. Although HAWC is designed to study gamma rays from galactic and extra-galactic sources, the large volume of instrumented water gives the opportunity to search for more exotic species. One such target, predicted by several varieties of supersymmetric theory, is the Q-ball. Q-balls are large, subrelativistic particles that can have a large baryon number and can be stable since their creation in the early universe. They are also a very appealing candidate for the dark matter of the universe, but their large masses must mean the flux is very low. HAWC has a flexible data acquisition system which, with a specialized trigger algorithm for non-relativistic species, allows a search for Q-balls traversing the detector. [Preview Abstract] |
Saturday, November 3, 2012 2:48PM - 3:00PM |
H1.00005: KAPAO: Implementing a Camera for Atmospheric Correction on the Table Mountain 1-meter Telescope Daniel Contreras Adaptive optics (AO) is a technology used on ground based telescopes to correct for atmospheric aberration in astronomical images. KAPAO, a Pomona College Adaptive Optics instrument, is currently in its third and final year of development. This dual-band (optical/IR) AO instrument is based on custom optics, a tip-tilt mirror, a 140 actuator microelectromechanical deformable mirror (MEMS DM) and a 1kHz wavefront sensor (WFS) camera. The system will be integrated onto the remote access Table Mountain Observatory (TMO) 1-meter telescope Recent work on KAPAO has focused on characterization of on-sky closed loop performance of the prototype system, Alpha. Special attention has been given to investigating the intensity and optical throughput of the system, researching improvements to the WFS component of the instrument, as well as improving the software control loop. This is all in preparation for the construction of the final system, Prime. Building the final system is set to begin in winter 2012-2013. [Preview Abstract] |
Saturday, November 3, 2012 3:00PM - 3:12PM |
H1.00006: KAPAO Prime: Design and Simulation Lorcan McGonigle KAPAO (KAPAO A Pomona Adaptive Optics instrument) is a dual-band natural guide star adaptive optics system designed to measure and remove atmospheric aberration from Pomona College's telescope atop Table Mountain. We present here, the final optical system, referred to as Prime, designed in Zemax Optical Design Software. Prime is characterized by diffraction limited imaging over the full 73'' field of view of our Andor~Camera at f/33 as well as for our NIR~Xenics~camera at f/50. In~Zemax, tolerances of 1{\%} on OAP focal length and off-axis distance were shown to contribute an additional 4 nm of~wavefront~error (98{\%} confidence) over the~field of view~of the~Andor~camera; the contribution from surface irregularity was determined analytically to be 40nm for~OAPs specified to l/10~surface irregularity. Modeling of the temperature deformation of the breadboard in~SolidWorks~revealed 70 micron contractions along the edges of the board for a decrease of 75\r{ }F; when applied to OAP positions such displacements from the optimal layout are predicted to contribute an additional 20 nanometers of~wavefront~error. Flexure modeling of the breadboard due to gravity is on-going. We hope to begin alignment and testing of ``Prime'' in Q1 2013. [Preview Abstract] |
Saturday, November 3, 2012 3:12PM - 3:24PM |
H1.00007: The protection of shock wave for Interstellar travel Yongfeng Wu Interstellar travel is definitely an important step for mankind in the future space exploration. Relativistic time dilation is then necessary to cover galaxy-scale distance in a reasonable amount of personal time. Consequently, interstellar hydrogen H, although only presents at a density of approximately 1.8 atoms/cm$^3$, will be a disaster for spaceships and passengers as it will turn to be a surprisingly high density flow with the effect of relativistic time dilation. Limiting the speed of spaceship may avoid severe H irradiation sets but this is inadequate for long distance trip in the universe. However, shock wave, automatically produced by high speed spaceship, will protect the spaceships and passengers from the radiation of H atoms. [Preview Abstract] |
Saturday, November 3, 2012 3:24PM - 3:36PM |
H1.00008: MEST- avoid next extinction Dayong Cao Asteroid 2011 AG5 will impact on Earth in 2040. (See Donald K. Yoemans, ``Asteroid 2011 AG5 - A Reality Check,'' NASA-JPL, 2012) In 2011, The author say: the dark hole will take the dark comet to impact our solar system in 20 years, and give a systemic model between the sun and its companion-dark hole to explain why were there periodicity mass extinction on earth. (see Dayong Cao, BAPS.2011.CAL.C1.7, BAPS.2011.DFD.LA.24, BAPS.2012.APR.K1.78 and BAPS.2011.APR.K1.17) The dark Asteroid 2011 AG5 (as a dark comet) is made of the dark matter which has a space-time (as frequence-amplitude square) center- a different systemic model from solar systemic model. It can asborb the space-time and wave. So it is ``dark.'' When many dark matters hit on our earth, they can break our atom structure and our genetic code to trigger the Mass Extinction. In our experiments, consciousness can change the systematic model and code by a life-informational technology. So it can change the output signals of the solar cell. (see Dayong Cao, BAPS.2011.MAR.C1.286 and BAPS.2012.MAR.P33.14) So we will develop the genetic code of lives to evolution and sublimation, will use the dark matter to change the systemic model between dark hole and sun and will avoid next extinction. [Preview Abstract] |
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