The Limitations of Optical Spectroscopic Diagnostics in Identifying AGNs in the Low Mass Regime. (arXiv:1812.06170v1 [astro-ph.GA]) <a href="">Jenna M. Cann</a>, <a href="">Shobita Satyapal</a>, <a href="">Nicholas P. Abel</a>, <a href="">Laura Blecha</a>, <a href="">Richard F. Mushotzky</a>, <a href="">Christopher S. Reynolds</a>, <a href="">Nathan J. Secrest</a> Intermediate-mass black holes (IMBHs) with masses between $100 – 10^5M_{odot}$ are crucial to our understanding of black hole seed formation and are the prime targets for LISA, yet black holes in this mass range have eluded detection by traditional optical spectroscopic surveys aimed at finding active galactic nuclei (AGNs). In this paper, we have modeled for the first time the dependence of theRead More →

The Transit Light Source Effect II: The Impact of Stellar Heterogeneity on Transmission Spectra of Planets Orbiting Broadly Sun-like Stars. (arXiv:1812.06184v1 [astro-ph.EP]) <a href="">Benjamin V. Rackham</a>, <a href="">D&#xe1;niel Apai</a>, <a href="">Mark S. Giampapa</a> Transmission spectra probe exoplanetary atmospheres, but they can also be strongly affected by heterogeneities in host star photospheres through the transit light source effect. Here we build upon our recent study of the effects of unocculted spots and faculae on M-dwarf transmission spectra, extending the analysis to FGK dwarfs. Using a suite of rotating model photospheres, we explore spot and facula covering fractions for varying activity levels and the associated stellar contaminationRead More →

The dense galactic environments of the Milky Way. (arXiv:1812.06187v1 [astro-ph.GA]) <a href="">Quang Nguyen-Luong</a>, <a href="">Neal Evans</a>, <a href="">Kee-Tae Kim</a>, <a href="">Hyunwoo Kang</a>, <a href="">DEGAMA survey members</a> Star formation takes place in the dense gas phase, and therefore a simple dense gas and star formation rate relation has been proposed. With the advent of multi-beam receivers, new observations show that the deviation from linear relations is possible. In addition, different dense gas tracers might also change significantly the measurement of dense gas mass and subsequently the relation between star formation rate and dense gas mass. We report the preliminary results the DEnse GAs in MAssive star-formingRead More →

Why Chromatic Imaging Matters. (arXiv:1812.06191v1 [astro-ph.IM]) <a href="">Joel Sanchez-Bermudez</a>, <a href="">Florentin Millour</a>, <a href="">Fabien Baron</a>, <a href="">Roy van Boekel</a>, <a href="">Laurent Bourg&#xe8;s</a>, <a href="">Gilles Duvert</a>, <a href="">Paulo J. V. Garcia</a>, <a href="">Nuno Gomes</a>, <a href="">Karl-Heinz Hofmann</a>, <a href="">Thomas Henning</a>, <a href="">Jacob W. Isbell</a>, <a href="">Bruno Lopez</a>, <a href="">Alexis Matter</a>, <a href="">J-Uwe Pott</a>, <a href="">Dieter Schertl</a>, <a href="">Eric Thi&#xe9;baut</a>, <a href="">Gerd Weigelt</a>, <a href="">John Young</a> During the last two decades, the first generation of beam combiners at the Very Large Telescope Interferometer has proved the importance of optical interferometry for high-angular resolution astrophysical studies in the near- and mid-infrared. With the advent of 4-beam combiners atRead More →

Flux Distribution of Gamma-Ray Emission in Blazars: The Example of Mrk 501. (arXiv:1812.06204v1 [astro-ph.HE]) <a href="">Carlo Romoli</a>, <a href="">Nachiketa Chakraborty</a>, <a href="">Daniela Dorner</a>, <a href="">Andrew M. Taylor</a>, <a href="">Michael Blank</a> (for the FACT and H.E.S.S. Collaborations) Flux distribution is an important tool to understand the variability processes in active galactic nuclei. We now have available a great deal of observational evidences pointing towards the presence of log-normal components in the high energy light curves, and different models have been proposed to explain these data. Here, we collect some of the recent developments on this topic using the well-known blazar Mrk 501 as example of complexRead More →

X-ray – Infrared relation of AGNs and search for highly obscured accretion in the AKARI NEP Field. (arXiv:1812.06208v1 [astro-ph.GA]) <a href="">Takamitsu Miyaji</a> (Instituto de Astronom&#xed;a sede Ensenada, Universidad Nacional Aut&#xf3;noma de M&#xe9;xico), <a href="">AKARI NEP Survey Team</a> The infrared Astronomical Satellite AKARI conducted deep ($sim$ 0.4 deg$^2$) and wide ($sim 5.4$ deg$^2$) surveys around the North Ecliptic Pole (NEP) with its InfraRed Camera (IRC) with nine filters continuously covering the 2-25 $mu$m range. These photometric bands include three filters that fill the Spitzer gap between the wavelength coverage with IRAC and MIPS instruments. This unique feature has enabled us to make sensitive mid-infrared detection ofRead More →

Pions near condensation under compact star conditions. (arXiv:1812.06213v1 [hep-ph]) <a href="">Cristian Villavicencio</a>, <a href="">Marcelo Loewe</a>, <a href="">Alfredo Raya</a> The behavior of pions is studied in systems where their normal leptonic decay is forbidden. When thermal fluctuations are present, a low decay rate is generated, and as a consequence of lepton recombination, the amount of pions remains almost unaltered. Compact stars conditions are favorable for the formation of such intermediate state of charged pions: near condensation and almost stable, leading to a continuum source of anti-neutrinos. In particular, protoneutron stars could be an scenario where this state of matter is relevant. The behavior of pions isRead More →

Intensity Mapping in the Presence of Foregrounds and Correlated Continuum Emission. (arXiv:1812.06223v1 [astro-ph.CO]) <a href="">E. R. Switzer</a>, <a href="">C. J. Anderson</a>, <a href="">A. R. Pullen</a>, <a href="">S. Yang</a> Intensity mapping has attracted significant interest as an approach to measure the properties of the interstellar medium in typical galaxies at high redshift. Intensity mapping measures the statistics of surface brightness as a function of frequency, making it sensitive not only to all line emission of interest but also radiation from all other sources. Significant effort has gone into developing approaches that reject foreground contamination. Additionally, the target galaxies have multiple sources of emission that can complicateRead More →

Walking Through an Exploded Star: Rendering Supernova Remnant Cassiopeia A into Virtual Reality. (arXiv:1812.06237v1 [astro-ph.IM]) <a href="">Kimberly K. Arcand</a>, <a href="">Elaine Jiang</a>, <a href="">Sara Price</a>, <a href="">Megan Watzke</a>, <a href="">Tom Sgouros</a>, <a href="">Peter Edmonds</a> NASA and other astrophysical data of the Cassiopeia A supernova remnant have been rendered into a three-dimensional virtual reality (VR) and augmented reality (AR) program, the first of its kind. This data-driven experience of a supernova remnant allows viewers to walk inside the leftovers from the explosion of a massive star, select the parts of the supernova remnant to engage with, and access descriptive texts on what the materials are. TheRead More →

The young star population of L1188. (arXiv:1812.06251v1 [astro-ph.SR]) <a href="">Elza Szegedi-Elek</a>, <a href="">M&#xe1;ria Kun</a>, <a href="">Attila Mo&#xf3;r</a>, <a href="">G&#xe1;bor Marton</a>, <a href="">Bo Reipurth</a> We present new results on the young star population of the Lynds~1188 molecular cloud, associated with the Cepheus Bubble, a giant interstellar shell around the association Cep~OB,2. In order to reveal the star-forming scenario of the molecular cloud located on the supershell, and understand the history of star formation in the region, we identified and characterized young star candidates based on an H$alpha$ emission survey and various published photometric datasets. Using Gaia DR2 astrometry we studied the spatial distribution of the youngRead More →

Improving Binary Millisecond Pulsar Distances with Gaia. (arXiv:1812.06262v1 [astro-ph.IM]) <a href="">Chiara M. F. Mingarelli</a>, <a href="">Lauren Anderson</a>, <a href="">Megan Bedell</a>, <a href="">David N. Spergel</a> Improved distance measurements to millisecond pulsars can enhance pulsar timing array (PTA) sensitivity to gravitational waves, improve tests of general relativity with binary pulsars, improve constraints on fuzzy dark matter, and more. Here we report the parallax distance measurements to six Gaia DR2 objects associated with International PTA pulsars J0437-4715, J1012+5307, J1024-0719, J1732-5049, J1910+1256, and J1843-1113. By multiplying the posteriors of the PTA distances with the gaia distance to the companion, we improve the distance measurements, and provide a tentative detectionRead More →

Interaction of hemispherical blast waves with inhomogeneous spheres: Probing the collision of a supernova ejecta with a nearby companion star in the laboratory. (arXiv:1812.06285v1 [astro-ph.SR]) <a href="">Domingo Garc&#xed;a-Senz</a>, <a href="">Pedro Velarde</a>, <a href="">Francisco Suzuki-Vidal</a>, <a href="">Chantal Stehl&#xe9;</a>, <a href="">Manuel Cotelo</a>, <a href="">David Portillo</a>, <a href="">Tomasz Plewa</a>, <a href="">Arthur Pak</a> Past high-energy density laboratory experiments provided insights into the physics of supernovae, supernova remnants, and the destruction of interstellar clouds. In a typical experimental setting, a laser-driven planar blast wave interacts with a compositionally-homogeneous spherical or cylindrical target. In this work we propose a new laboratory platform that accounts for curvature of the impacting shock andRead More →

A faint halo star cluster discovered in the Blanco Imaging of the Southern Sky Survey. (arXiv:1812.06318v1 [astro-ph.GA]) <a href="">S. Mau</a>, <a href="">A. Drlica-Wagner</a>, <a href="">K. Bechtol</a>, <a href="">A. B. Pace</a>, <a href="">T. Li</a>, <a href="">M. Soares-Santos</a>, <a href="">N. Kuropatkin</a>, <a href="">S. Allam</a>, <a href="">D. Tucker</a>, <a href="">L. Santana-Silva</a>, <a href="">B. Yanny</a>, <a href="">P. Jethwa</a>, <a href="">A. Palmese</a>, <a href="">K. Vivas</a>, <a href="">C. Burgad</a>, <a href="">H.-Y. Chen</a> We present the discovery of a faint, resolved stellar system, BLISS J0321+0438 (BLISS 1), found in Dark Energy Camera data from the first observing run of the Blanco Imaging of the Southern Sky (BLISS) Survey. BLISS J0321+0438 (BLISS 1)Read More →

The Origin of the Multiwavelength Emission of PKS 0502+049. (arXiv:1812.06338v1 [astro-ph.HE]) <a href="">N. Sahakyan</a> The origin of the multiwavelength emission from PKS 0502+049 neighboring the first cosmic neutrino source TXS 0506+056 is studied using the data observed by Fermi-LAT and Swift UVOT/XRT. This source was in a flaring state in the considered bands before and after the neutrino observations in 2014-2015, characterized by hard emission spectra in the X-ray and $gamma$-ray bands, $1.5-1.8$ and $leq2.0$, respectively. During the neutrino observations, the $gamma$-ray spectrum shows a deviation from a simple power-law shape, indicating a spectral cutoff at $E_c =8.50pm2.06$ GeV. The spectral energy distributions of PKSRead More →

New Near-Infrared $JHK_s$ light-curve templates for RR Lyrae variables. (arXiv:1812.06372v1 [astro-ph.SR]) <a href="">V.F. Braga</a> (1,2), <a href="">P.B. Stetson</a> (3), <a href="">G. Bono</a> (4,5), <a href="">M. Dall&#x27;Ora</a> (6), <a href="">I. Ferraro</a> (5), <a href="">G. Fiorentino</a> (7), <a href="">G. Iannicola</a> (5), <a href="">L. Inno</a> (8), <a href="">M. Marengo</a> (9), <a href="">J. Neeley</a> (10), <a href="">R.L. Beaton</a> (11), <a href="">R. Buonanno</a> (12), <a href="">A. Calamida</a> (13), <a href="">R. Contreras Ramos</a> (14), <a href="">B. Chaboyer</a> (15), <a href="">M. Fabrizio</a> (16), <a href="">W.L. Freedman</a> (17), <a href="">C.K. Gilligan</a> (15), <a href="">K.V. Johnston</a> (18), <a href="">B.F. Madore</a> (11), <a href="">D. Magurno</a> (4), <a href="">M. Marconi</a> (6), <a href="">S. Marinoni</a> (16), <aRead More →

First observations with the 25 cm telescope of the Shumen Astronomical Observatory. (arXiv:1812.06388v1 [astro-ph.IM]) <a href="">Diana Kjurkchieva</a>, <a href="">Sunay Ibryamov</a>, <a href="">Borislav Borisov</a>, <a href="">Dragomir Marchev</a>, <a href="">Velimir Popov</a>, <a href="">Dinko Dimitrov</a> The first observations with the 25 cm telescope of the Shumen Astronomical Observatory led to the following conclusions: (a) Intra-night observations of variable stars with an amplitude larger than 0.1 mag are possible down to 14 mag with an acceptable quality with this setup; (b) The equipment is suitable for observations of bright extended objects with sizes up to 30 arcmin (planets, comets, clusters, nebulae, galaxies) with resolution 0.88 arcsec/pix; (c) The guidingRead More →

Starspot rotation rates vs. activity cycle phase: Butterfly diagrams of Kepler stars are unlike the Sun’s. (arXiv:1812.06414v1 [astro-ph.SR]) <a href="">M. B. Nielsen</a>, <a href="">L. Gizon</a>, <a href="">R. H. Cameron</a>, <a href="">M. Miesch</a> During the solar magnetic activity cycle the emergence latitudes of sunspots change, leading to the well-known butterfly diagram. This phenomenon is poorly understood for other stars as starspot latitudes are generally unknown. The related changes in starspot rotation rates caused by latitudinal differential rotation can however be measured. Using the set of 3093 Kepler stars with activity cycles identified by Reinhold et al. (2017), we aim to study the temporal change in starspotRead More →

Energy release from magnetospheres deformed by gravitational waves. (arXiv:1812.06430v1 [astro-ph.HE]) <a href="">Huiquan Li</a>, <a href="">Jiancheng Wang</a> In this work, we consider the possibility of energy release in pulsar magnetospheres deformed by gravitational waves from nearby sources. The strong electromagnetic fields in the magnetospheres may release non-negligible energy despite the weakness of the gravitational wave. When the background spacetime is perturbed due to the passage of a gravitational wave, the original force-free state of the inner magnetosphere will be slightly violated. The plasma-filled magnetosphere tends to evolve into new force-free states as the spacetime varies with time. During this process, a small portion of the electromagneticRead More →

Isochrone fitting of Galactic globular clusters – I. NGC 5904. (arXiv:1812.06433v1 [astro-ph.GA]) <a href="">George A. Gontcharov</a>, <a href="">Aleksandr V. Mosenkov</a>, <a href="">Maxim Yu. Khovritchev</a> We present new isochrone fits to colour-magnitude diagrams of the Galactic globular cluster NGC 5904 (M5). We utilise 29 photometric bands from the ultraviolet to mid-infrared by use of the data from the {it Hubble Space Telescope}, {it Gaia} DR2, {it Wide-field Infrared Survey Explorer}, Sloan Digital Sky Survey (SDSS), and other photometric data. In our isochrone fitting we use the PAdova and TRieste Stellar Evolution Code, the MESA Isochrones and Stellar Tracks, the Dartmouth Stellar Evolution Program, and a BagRead More →

Galactic astronomy and small telescopes. (arXiv:1812.06461v1 [astro-ph.IM]) <a href="">Toma&#x17e; Zwitter</a> The second data release of ESA’s Gaia satellite (Gaia DR2) revolutionised astronomy by providing accurate distances, proper motions, apparent magnitudes, and in many cases temperatures and radial velocities for an unprecedented number of stars. These new results, which are freely available, need to be considered in virtually any stellar research project, as they provide crucial information on luminosity, position, motion, orbit, and colours of observed targets. Ground-based spectroscopic surveys, like RAVE, Gaia-ESO, Apogee, LAMOST, and GALAH, are adding more measurements of radial velocities and, most importantly, chemistry of stellar atmospheres, including abundances of individual elements.Read More →