External Galaxies Commons^™

A Luminous And Isolated Gamma-Ray Flare From The Blazar B2 1215+30, A. U. Abeysekara, S. Archambault, A. Archer, W. Benbow, R. Bird, M. Buchovecky, J H. Buckley, V. Bugaev, K. Byrum, P. T. Reynolds, Et Al

Physical Sciences Publications

B2 1215+30 is a BL-Lac-type blazar that was first detected at TeV energies by the MAGIC atmospheric Cherenkov telescopes and subsequently confirmed by the Very Energetic Radiation Imaging Telescope Array System (VERITAS) observatory with data collected between 2009 and 2012. In 2014 February 08, VERITAS detected a large-amplitude flare from B2 1215+30 during routine monitoring observations of the blazar 1ES 1218+304, located in the same field of view. The TeV flux reached 2.4 times the Crab Nebula flux with a variability timescale of . Multiwavelength observations with Fermi-LAT, Swift, and the Tuorla Observatory revealed a correlated high GeV …

A Multiwavelength Continuum Characterization Of High-Redshift Broad Absorption Line Quasars, D. Tuccillo, G. Bruni, M. A. Dipompeo, M. S. Brotherton

Dartmouth Scholarship

We present the results of a multiwavelength study of a sample of high-redshift radio-loud (RL) broad absorption line (BAL) quasars. This way, we extend to higher redshift previous studies on the radio properties and broad-band optical colours of these objects. We have selected a sample of 22 RL BAL quasars with 3.6 ≤ z ≤ 4.8 cross-correlating the FIRST radio survey with the Sloan Digital Sky Survey (SDSS). Flux densities between 1.25 and 9.5 GHz have been collected with the Jansky Very Large Array and Effelsberg-100 m telescopes for 15 BAL and 14 non-BAL quasars used as a comparison sample. …

The Sluggs Survey: Stellar Masses And Effective Radii Of Early-Type Galaxies From Spitzer Space Telescope 3.6 Μm Imaging, Duncan Forbes, Luciana Sinpetru, Giulia Savorgnan, Aaron Romanowsky, Christopher Usher, Jean Brodie

Faculty Publications

Galaxy starlight at 3.6 μm is an excellent tracer of stellar mass. Here we use the latest 3.6 μm imaging from the Spitzer Space Telescope to measure the total stellar mass and effective radii in a homogeneous way for a sample of galaxies from the SAGES Legacy Unifying Globulars and GalaxieS (SLUGGS) survey. These galaxies are representative of nearby early-type galaxies in the stellar mass range of 10 < log M*/M⊙ < 11.7 and our methodology can be applied to other samples of early-type galaxies. We model each galaxy in 2D and estimate its total asymptotic magnitude from a 1D curve-of-growth. Magnitudes are converted into stellar masses using a 3.6 μm mass-to-light ratio from the latest stellar population models of Röck et al., assuming a Kroupa initial mass function. We apply a ratio based on each galaxy's mean mass-weighted stellar age within one effective radius (the mass-to-light ratio is insensitive to galaxy metallicity for the generally old stellar ages and high metallicities found in massive early-type galaxies). Our 3.6 μm stellar masses agree well with masses derived from 2.2 μm data. From the 1D surface brightness profile, we fit a single Sérsic law, excluding the very central regions. We measure the effective radius, Sérsic n parameter and effective surface brightness for each galaxy. We find that galaxy sizes derived from shallow optical imaging and the 2MASS survey tend to underestimate the true size of the largest, most massive galaxies in our sample. We adopt the 3.6 μm stellar masses and effective radii for the SLUGGS survey galaxies.

Constraining The Physical State Of The Hot Gas Halos In Ngc 4649 And Ngc 5846, Alessandro Paggi, Dong-Woo Kim, Craig Anderson, Doug Burke, Raffaele D'Abrusco, Giuseppina Fabbiano, Antonella Fruscione, Tara Gokas, Jen Lauer, Michael Mccollough, Doug Morgan, Amy Mossman, Ewan O'Sullivan, Ginevra Trinchieri, Saeqa Vrtilek, Silvia Pellegrini, Aaron Romanowsky, Jean Brodie

Faculty Publications

We present results of a joint Chandra/XMM-Newton analysis of the early-type galaxies NGC 4649 and NGC 5846 aimed at investigating differences between mass profiles derived from X-ray data and those from optical data, to probe the state of the hot interstellar medium (ISM) in these galaxies. If the hot ISM is at a given radius in hydrostatic equilibrium (HE), the X-ray data can be used to measure the total enclosed mass of the galaxy. Differences from optically derived mass distributions therefore yield information about departures from HE in the hot halos. The X-ray mass profiles in different angular …

Quantum Foundations With Astronomical Photons, Calvin Leung

HMC Senior Theses

Bell's inequalities impose an upper limit on correlations between measurements of two-photon states under the assumption that the photons play by a set of local rules rather than by quantum mechanics. Quantum theory and decades of experiments both violate this limit.

Recent theoretical work in quantum foundations has demonstrated that a local realist model can explain the non-local correlations observed in experimental tests of Bell's inequality if the underlying probability distribution of the local hidden variable depends on the choice of measurement basis, or ``setting choice''. By using setting choices determined by astrophysical events in the distant past, it is …

Data Mining By Grid Computing In The Search For Extrasolar Planets, Oisin Creaner [Thesis]

Doctoral

A system is presented here to provide improved precision in ensemble differential photometry. This is achieved by using the power of grid computing to analyse astronomical catalogues. This produces new catalogues of optimised pointings for each star, which maximise the number and quality of reference stars available. Astronomical phenomena such as exoplanet transits and small-scale structure within quasars may be observed by means of millimagnitude photometric variability on the timescale of minutes to hours. Because of atmospheric distortion, ground-based observations of these phenomena require the use of differential photometry whereby the target is compared with one or more reference stars. …

An Outline Of Cellular Automaton Universe Via Cosmological Kdv Equation, Florentin Smarandache, Victor Christianto, Yunita Umniyati

Branch Mathematics and Statistics Faculty and Staff Publications

It has been known for long time that the cosmic sound wave was there since the early epoch of the Universe. Signatures of its existence are abound. However, such a sound wave model of cosmology is rarely developed fully into a complete framework. This paper can be considered as our second attempt towards such a complete description of the Universe based on soliton wave solution of cosmological KdV equation. Then we advance further this KdV equation by virtue of Cellular Automaton method to solve the PDEs. We submit wholeheartedly Robert Kuruczs hypothesis that Big Bang should be replaced with a …

On The Redshift Distribution And Physical Properties Of Act-Selected Dsfgs, T. Su, T. A. Marriage, V. Asboth, A. J. Baker, J. R. Bond, D. Crichton, M. J. Devlin, R. Dünner, D. Farrah, D. T. Frayer, M. B. Gralla, K. Hall, M. Halpern, A. I. Harris, M. Hilton, A. D. Hincks, J. P. Hughes, M. D. Niemack, L. A. Page, B. Partridge, J. Rivera, D. Scott, J. L. Sievers, Robert J. Thornton, M. P. Viero, L. Wang, E. J. Wollack, M. Zemcov

Physics & Engineering Faculty Publications

No abstract provided.

The Sluggs Survey: A Catalog Of Over 4000 Globular Cluster Radial Velocities In 27 Nearby Early-Type Galaxies, Duncan Forbes, Adebusola Alabi, Jean Brodie, Aaron Romanowsky, Jay Strader, Caroline Foster, Christopher Usher, Lee Spitler, Sabine Bellstedt, Nicola Pastorello, Alexa Villaume, Asher Wasserman, Vincenzo Pota

Faculty Publications

No abstract provided.

The Sluggs Survey: Revisiting The Correlation Between X-Ray Luminosity And Total Mass Of Massive Early-Type Galaxies, Duncan Forbes, Adebusola Alabi, Aaron Romanowsky, Dong-Woo Kim, Jean Brodie, Giuseppina Fabbiano

Faculty Publications

Here we utilize recent measures of galaxy total dynamical mass and X-ray gas luminosities (LX,Gas) for a sample of 29 massive early-type galaxies from the SLUGGS survey to probe LX, Gas–mass scaling relations. In particular, we investigate scalings with stellar mass, dynamical mass within 5 effective radii (Re) and total virial mass. We also compare these relations with predictions from Λ cold dark matter simulations. We find a strong linear relationship between LX, Gas and galaxy dynamical mass within 5Re, which is consistent with the recent cosmological simulations of Choi et al. that incorporate mechanical heating from AGN. We conclude …

Extensive Globular Cluster Systems Associated With Ultra Diffuse Galaxies In The Coma Cluster, Pieter Van Dokkum, Roberto Abraham, Aaron Romanowsky, Jean Brodie, Charlie Conroy, Shany Danieli, Deborah Lokhors, Allison Merritt, Lamiya Mowla, Jielai Zhang

Faculty Publications

We present Hubble Space Telescope (HST) imaging of two ultra diffuse galaxies (UDGs) with measured stellar velocity dispersions in the Coma cluster. The galaxies, Dragonfly 44 and DFX1, have effective radii of 4.7 kpc and 3.5 kpc and velocity dispersions of km s−1 and km s−1, respectively. Both galaxies are associated with a striking number of compact objects, tentatively identified as globular clusters: for Dragonfly 44 and for DFX1. The number of globular clusters is much higher than expected from the luminosities of the galaxies but is consistent with expectations from the empirical relation between dynamical mass and globular cluster …

A Scuba-2 Survey Of Felobal Qsos. Are Felobals In A ‘Transition Phase’ Between Ulirgs And Qsos?, Giulio Violino, Kristen E. K. Coppin, Jason A. Stevens, Duncan Farrah, James E. Geach, Dave M. Alexander, Ryan Hickox

Dartmouth Scholarship

It is thought that a class of broad absorption line (BAL) QSOs, characterised by Fe absorption features in their UV spectra (called `FeLoBALs'), could mark a transition stage between the end of an obscured starburst event and a youthful QSO beginning to shed its dust cocoon, where Fe has been injected into the interstellar medium by the starburst. To test this hypothesis we have undertaken deep SCUBA-2 850 μm observations of a sample of 17 FeLoBAL QSOs with 0.89 ≤ z ≤ 2.78 and -23.31 ≤ MB ≤-28.50 to directly detect an excess in the thermal emission of the dust …

X-Ray Detected Active Galactic Nuclei In Dwarf Galaxies At 0 < Z < 1, K. Pardo, A. D. Goulding, J. E. Greene, R. S. Somerville, E. Gallo, R. C. Hickox

Dartmouth Scholarship

We present a sample of accreting supermassive black holes (SMBHs) in dwarf galaxies at z\lt 1. We identify dwarf galaxies in the NEWFIRM Medium Band Survey with stellar masses of {M}_\star \lt 3× {10}⁹ {M}_⊙ that have spectroscopic redshifts from the DEEP2 survey and lie within the region covered by deep (flux limit of ˜ 5× {10}^-17{--}6× {10}^-16 {erg} {{cm}}^-2 {{{s}}}^-1) archival Chandra X-ray data. From our sample of 605 dwarf galaxies, 10 exhibit X-ray emission consistent with that arising from active galactic nucleus (AGN) activity. If black-hole mass scales roughly …

A Search For Very High-Energy Gamma Rays From The Missing Link Binary Pulsar J1023+0038 With Veritas, P. T. Reynolds, Et Al

Physical Sciences Publications

The binary millisecond radio pulsar PSR J1023+0038 exhibits many characteristics similar to the gamma-ray binary system PSR B1259–63/LS 2883, making it an ideal candidate for the study of high-energy nonthermal emission. It has been the subject of multiwavelength campaigns following the disappearance of the pulsed radio emission in 2013 June, which revealed the appearance of an accretion disk around the neutron star. We present the results of very high energy (VHE) gamma-ray observations carried out by the Very Energetic Radiation Imaging Telescope Array System before and after this change of state. Searches for steady and pulsed emission of both data …

A Discrete Chemo-Dynamical Model Of The Giant Elliptical Galaxy Ngc 5846: Dark Matter Fraction, Internal Rotation, And Velocity Anisotropy Out To Six Effective Radii, Ling Zhu, Aaron Romanowsky, Glenn Van De Ven, R. Long, Laura Watkins, Vincenzo Pota, Nicola Napolitano, Duncan Forbes, Jean Brodie, Caroline Foster

Faculty Publications

We construct a suite of discrete chemo-dynamical models of the giant elliptical galaxy NGC 5846. These models are a powerful tool to constrain both the mass distribution and internal dynamics of multiple tracer populations. We use Jeans models to simultaneously fit stellar kinematics within the effective radius Re, planetary nebula (PN) radial velocities out to 3 Re, and globular cluster (GC) radial velocities and colours out to 6 Re. The best-fitting model is a cored dark matter halo which contributes ∼10 per cent of the total mass within 1 Re, and 67 per cent ± 10 per cent within 6 …

The Mid-Infrared Luminosity Evolution And Luminosity Function Of Quasars With Wise And Sdss, Jack Singal

Physics Faculty Publications

We determine the 22 μm luminosity evolution and luminosity function for quasars from a data set of over 20,000 objects obtained by combining flux-limited Sloan Digital Sky Survey optical and Wide field Infrared Survey Explorer mid-infrared data. We apply methods developed in previous works to access the intrinsic population distributions non-parametrically, taking into account the truncations and correlations inherent in the data. We find that the population of quasars exhibits positive luminosity evolution with redshift in the mid-infrared, but with considerably less mid-infrared evolution than in the optical or radio bands. With the luminosity evolutions accounted for, we determine …

Very High Energy Observations Of The Binaries V 404 Cyg And 4u 0115+634 During Giant X-Ray Outbursts, P. T. Reynolds, Et Al

Physical Sciences Publications

Transient X-ray binaries produce major outbursts in which the X-ray flux can increase over the quiescent level by factors as large as 107. The low-mass X-ray binary V 404 Cyg and the high-mass system 4U 0115+634 underwent such major outbursts in 2015 June and October, respectively. We present here observations at energies above hundreds of GeV with the VERITAS observatory taken during some of the brightest X-ray activity ever observed from these systems. No gamma-ray emission has been detected by VERITAS in 2.5 hr of observations of the microquasar V 404 Cyg from 2015, June 20–21. The upper flux limits …

Ultraluminous X-Ray Bursts In Two Ultracompact Companions To Nearby Elliptical Galaxies, Jimmy Irwin, W. Maksym, Gregory Sivakoff, Aaron Romanowsky, Dacheng Lin, Tyler Speegle, Ian Prado, David Mildebrath, Jay Strader, Jifeng Liu, Jon Miller

Faculty Publications

A search of archival X-ray data for 70 nearby galaxies has yielded two flaring sources in globular clusters or ultracompact dwarf companions of parent elliptical galaxies. One source flared once, and the other five times. When not flaring, these sources appear to be normal accreting neutron-star or black-hole X-ray binaries. Unlike magnetars and other bodies that produce repetitive flares of similar luminosity, they are located in old stellar populations.

Deep Chandra Observations Of The Compact Starburst Galaxy Henize 2–10: X-Rays From The Massive Black Hole, Amy E. Reines, Mark T. Reynolds, Jon M. Miller, Gregory R. Sivakoff, Jenny E. Greene, Ryan C. Hickox, Kelsey E. Johnson

Dartmouth Scholarship

We present follow-up X-ray observations of the candidate massive black hole (BH) in the nucleus of the low-mass, compact starburst galaxy Henize 2–10. Using new high-resolution observations from the Chandra X-ray Observatory totaling 200 ks in duration, as well as archival Chandraobservations from 2001, we demonstrate the presence of a previously unidentified X-ray point source that is spatially coincident with the known nuclear radio source in Henize 2–10 (i.e., the massive BH). We show that the hard X-ray emission previously identified in the 2001 observation is dominated by a source that is distinct from the nucleus, with the properties …

Gama/H-Atlas : Common Star Formation Rate Indicators And Their Dependence On Galaxy Physical Parameters., L. Wang, P. Norberg, M. L. P. Gunawardhana, S. Heinis, I. K. Baldry, J. Bland-Hawthorn, N. Bourne, S. Brough, M. J. I. Brown, M. E. Cluver, A. Cooray, E. Da Cunha, S. P. Driver, L. Dunne, S. Dye, S. Eales, M. W. Grootes, Benne W. Holwerda, A. M. Hopkins, E. Ibar, R. Ivison, C. Lacey, M. A. Lara-Lopez, J. Loveday, S. J. Maddox, M. J. Michalowski, I. Oteo, M. S. Owers, C. C. Popescu, D. J. B. Smith, E. N. Taylor, R. J. Tuffs, P. Van Der Werf

Faculty and Staff Scholarship

We compare common star formation rate (SFR) indicators in the local Universe in the Galaxy and Mass Assembly (GAMA) equatorial fields (∼160 deg2), using ultraviolet (UV) photometry from GALEX, far-infrared and sub-millimetre (sub-mm) photometry from Herschel Astrophysical Terahertz Large Area Survey, and Hα spectroscopy from the GAMA survey. With a high-quality sample of 745 galaxies (median redshift z = 0.08), we consider three SFR tracers: UV luminosity corrected for dust attenuation using the UV spectral slope β (SFRUV, corr), Hα line luminosity corrected for dust using the Balmer decrement (BD) (SFRH α, corr), and the combination of UV and infrared …