RAS_WEB (Page 4,070)

Deciphering the Nature of the Pulsar Wind Nebula CTB 87 with XMM-Newton. (arXiv:1911.11829v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Guest_B/0/1/0/all/0/1">Benson Guest</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Safi_Harb_S/0/1/0/all/0/1">Samar Safi-Harb</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+MacMaster_A/0/1/0/all/0/1">Austin MacMaster</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kothes_R/0/1/0/all/0/1">Roland Kothes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Olmi_B/0/1/0/all/0/1">Barbara Olmi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Amato_E/0/1/0/all/0/1">Elena Amato</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bucciantini_N/0/1/0/all/0/1">Niccolo Bucciantini</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Arzoumanian_Z/0/1/0/all/0/1">Zaven Arzoumanian</a> CTB 87 (G74.9+1.2) is an evolved supernova remnant (SNR) which hosts a peculiar pulsar wind nebula (PWN). The X-ray peak is offset from that observed in radio and lies towards the edge of the radio nebula. The putative pulsar, CXOU~J201609.2+371110, was first resolved with textit{Chandra} and is surrounded by a compact and a more extended X-ray nebula. Here we use a deep {textit{XMM-Newton}} observation to examine theRead More →

Efficient Gravitational-wave Glitch Identification from Environmental Data Through Machine Learning. (arXiv:1911.11831v1 [astro-ph.IM]) <a href="http://arxiv.org/find/astro-ph/1/au:+Colgan_R/0/1/0/all/0/1">Robert E. Colgan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Corley_K/0/1/0/all/0/1">K. Rainer Corley</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lau_Y/0/1/0/all/0/1">Yenson Lau</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bartos_I/0/1/0/all/0/1">Imre Bartos</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wright_J/0/1/0/all/0/1">John N. Wright</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Marka_Z/0/1/0/all/0/1">Zsuzsa Marka</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Marka_S/0/1/0/all/0/1">Szabolcs Marka</a> The LIGO observatories detect gravitational waves through monitoring changes in the detectors’ length down to below $10^{-19}$,$m/sqrt{Hz}$ variation—a small fraction of the size of the atoms that make up the detector. To achieve this sensitivity, the detector and its environment need to be closely monitored. Beyond the gravitational wave data stream, LIGO continuously records hundreds of thousands of channels of environmental and instrumental data in order to monitor possibleRead More →

Testing Modified Gravity with Acceleration Relations in the Milky Way. (arXiv:1911.11836v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Islam_T/0/1/0/all/0/1">Tousif Islam</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dutta_K/0/1/0/all/0/1">Koushik Dutta</a> The dynamical mass of galaxies and the Newtonian acceleration generated from the baryons have been found to be strongly correlated. This correlation is known as ‘Mass-Discrepancy Acceleration Relation’ (MDAR). Further investigations have revealed a tighter relation – ‘Radial Acceleration Relation’ (RAR) – between the observed total acceleration and the (Newtonian) acceleration produced by the baryons. So far modified gravity theories have remained more successful than $Lambda$CDM to explain these relations. However, a recent investigation has pointed out that, when RAR is expressed as a difference between theRead More →

Cross Correlation of the Extragalactic Gamma-ray Background with Thermal Sunyaev-Zel’dovich Effect in the Cosmic Microwave Background. (arXiv:1911.11841v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Shirasaki_M/0/1/0/all/0/1">Masato Shirasaki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Macias_O/0/1/0/all/0/1">Oscar Macias</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ando_S/0/1/0/all/0/1">Shin&#x27;ichiro Ando</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Horiuchi_S/0/1/0/all/0/1">Shunsaku Horiuchi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yoshida_N/0/1/0/all/0/1">Naoki Yoshida</a> Cosmic rays in galaxy clusters are unique probes of energetic processes operating with large-scale structures in the Universe. Precise measurements of cosmic rays in galaxy clusters are essential for improving our understanding of non-thermal components in the intracluster-medium (ICM) as well as the accuracy of cluster mass estimates in cosmological analyses. In this paper, we perform a cross-correlation analysis with the extragalactic gamma-ray background and the thermal Sunyaev-Zel’dovich (tSZ) effect in theRead More →

Freeze-in production of dark matter through spin-1 and spin-2 portals. (arXiv:1911.11844v1 [hep-ph]) <a href="http://arxiv.org/find/hep-ph/1/au:+Dutra_M/0/1/0/all/0/1">Ma&#xed;ra Dutra</a> In this conference, I have talked about two scenarios in which the out-of-equilibrium production of dark matter (DM) particles in the early universe is unavoidable. In the first one cite{bhattacharyya_freezing-dark_2018}, we extend the standard model (SM) of particle physics by an extra $U(1)$ gauge group under which all the SM particles are neutral. We then consider DM candidates interacting only with the new spin-1 gauge boson, a heavy $Z^prime$. We assume the presence of heavy beyond the SM fermions charged under both extra $U(1)$ and SM $SU(3)_c$, allowing for aRead More →

Is the Hubble diagram of quasars in tension with concordance cosmology?. (arXiv:1911.11848v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Velten_H/0/1/0/all/0/1">Hermano Velten</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gomes_S/0/1/0/all/0/1">Syrios Gomes</a> Recently Risaliti & Lusso [Nature Astron. 3 (2019) 3 272] reported new measurements of the expansion rate of the Universe by constructing the Hubble diagram of 1598 quasars in the redshift range $0.5Read More →

The Distinction Between Thermal Nonequilibrium and Thermal Instability. (arXiv:1911.11849v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Klimchuk_J/0/1/0/all/0/1">James A. Klimchuk</a> For some forms of steady heating, coronal loops are in a state of thermal nonequilibrium and evolve in a manner that includes accelerated cooling, often resulting in the formation of a cold condensation. This is frequently confused with thermal instability, but the two are in fact fundamentally different. We explain the distinction and discuss situations where they may be interconnected. Large-amplitude perturbations, perhaps associated with MHD waves, likely play a role in explaining phenomena that have been attributed to thermal nonequilibrium but also seem to require cross-field communication. For some formsRead More →

Charge exchange emission and cold clumps in multi-phase galactic outflows. (arXiv:1911.11860v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Wu_K/0/1/0/all/0/1">Kinwah Wu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_K/0/1/0/all/0/1">Kaye Jiale Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Owen_E/0/1/0/all/0/1">Ellis R. Owen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ji_L/0/1/0/all/0/1">Li Ji</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_S/0/1/0/all/0/1">Shuinai Zhang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Branduardi_Raymont_G/0/1/0/all/0/1">Graziella Branduardi-Raymont</a> Large-scale outflows from starburst galaxies are multi-phase, multi-component fluids. Charge-exchange lines which originate from the interfacing surface between the neutral and ionised components are a useful diagnostic of the cold dense structures in the galactic outflow. From the charge-exchange lines observed in the nearby starburst galaxy M82, we conduct surface-to-volume analyses and deduce that the cold dense clumps in its galactic outflow have flattened shapes, resembling a hamburger or a pancake morphology ratherRead More →

The moduli portal to dark matter particles. (arXiv:1911.11862v1 [hep-ph]) <a href="http://arxiv.org/find/hep-ph/1/au:+Dutra_M/0/1/0/all/0/1">Ma&#xed;ra Dutra</a> The out-of-equilibrium production of dark matter (DM) from standard model (SM) species in the early universe (freeze-in mechanism) is expected in many scenarios in which very heavy beyond the SM fields act as mediators. In this conference, I have talked about the freeze-in of scalar, fermionic and vector DM though the exchange of moduli fields cite{chowdhury_moduli_2019}, which are in the low-energy spectrum of many extra-dimensions and string theory frameworks. We have shown that the high-temperature dependencies of the production rate densities in this model, as well as the possibility of having moduli massesRead More →

Mass models of gas-rich void dwarf galaxies. (arXiv:1911.11877v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Kurapati_S/0/1/0/all/0/1">Sushma Kurapati</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chengalur_J/0/1/0/all/0/1">Jayaram N. Chengalur</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kamphuis_P/0/1/0/all/0/1">Peter Kamphuis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pustilnik_S/0/1/0/all/0/1">Simon Pustilnik</a> We construct mass models of eight gas rich dwarf galaxies that lie in the Lynx-Cancer void. From NFW fits to the dark matter halo profile, we find that the concentration parameters of halos of void dwarf galaxies are similar to those of dwarf galaxies in normal density regions. We also measure the slope of the central dark matter density profiles, obtained by converting the rotation curves derived using 3-D (fat) and 2-D (ROTCUR) tilted ring fitting routines, into mass densities. We find thatRead More →

New Perspectives on Axion Misalignment Mechanism. (arXiv:1911.11885v1 [hep-ph]) <a href="http://arxiv.org/find/hep-ph/1/au:+Chang_C/0/1/0/all/0/1">Chia-Feng Chang</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Cui_Y/0/1/0/all/0/1">Yanou Cui</a> A zero initial velocity of the axion field is assumed in the conventional misalignment mechanism. We propose an alternative scenario where the initial velocity is nonzero, which may arise from an explicit breaking of the PQ symmetry in the early Universe. We demonstrate that, depending on the specifics about the initial velocity and the time order of the PQ symmetry breaking vs. inflation, this new scenario can alter the conventional prediction for the axion relic abundance in different, potentially significant ways. As a result, new viable parameter regions for axion darkRead More →

The ALMaQUEST Survey: III. Scatter in the resolved star forming main sequence is primarily due to variations in star formation efficiency. (arXiv:1911.11887v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Ellison_S/0/1/0/all/0/1">Sara L. Ellison</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Thorp_M/0/1/0/all/0/1">Mallory D. Thorp</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lin_L/0/1/0/all/0/1">Lihwai Lin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pan_H/0/1/0/all/0/1">Hsi-An Pan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bluck_A/0/1/0/all/0/1">Asa F. L. Bluck</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Scudder_J/0/1/0/all/0/1">Jillian M. Scudder</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Teimoorinia_H/0/1/0/all/0/1">Hossen Teimoorinia</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sanchez_S/0/1/0/all/0/1">Sebastian F. Sanchez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sargent_M/0/1/0/all/0/1">Mark Sargent</a> Using a sample of 11,478 spaxels in 34 galaxies with molecular gas, star formation and stellar maps taken from the ALMA-MaNGA QUEnching and STar formation (ALMaQUEST) survey, we investigate the parameters that correlate with variations in star formation rates on kpc scales. We use a combination of correlation statisticsRead More →

Design of a testbed for the study of system interference in space CMB polarimetry. (arXiv:1911.11902v1 [astro-ph.IM]) <a href="http://arxiv.org/find/astro-ph/1/au:+Ghigna_T/0/1/0/all/0/1">Tommaso Ghigna</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Matsumura_T/0/1/0/all/0/1">Tomotake Matsumura</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hazumi_M/0/1/0/all/0/1">Masashi Hazumi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stever_S/0/1/0/all/0/1">Samantha Lynn Stever</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sakurai_Y/0/1/0/all/0/1">Yuki Sakurai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Katayama_N/0/1/0/all/0/1">Nobuhiko Katayama</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Suzuki_A/0/1/0/all/0/1">Aritoki Suzuki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Westbrook_B/0/1/0/all/0/1">Benjamin Westbrook</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lee_A/0/1/0/all/0/1">Adrian Lee</a> LiteBIRD is a proposed JAXA satellite mission to measure the CMB B-mode polarization with unprecedented sensitivity ($sigma_rsim 0.001$). To achieve this goal, $4676$ state-of-the-art TES bolometers will observe the whole sky for 3 years from L2. These detectors, as well as the SQUID readout, are extremely susceptible to EMI and other instrumental disturbances e.g. static magnetic field and vibration. As aRead More →

The Andromeda System: A new orbital history and its implications. (arXiv:1911.11911v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Tepper_Garcia_T/0/1/0/all/0/1">Thor Tepper-Garc&#xed;a</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bland_Hawthorn_J/0/1/0/all/0/1">Joss Bland-Hawthorn</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_D/0/1/0/all/0/1">Di Li</a> We revisit the orbital history of the Triangulum galaxy (M33) around the Andromeda galaxy (M31) in view of the recent Gaia Data Release 2 proper motion measurements for both Local Group galaxies. Earlier studies consider highly idealized dynamical friction, but neglect the effects of dynamical mass loss. We show the latter process to be important using orbit integrations and N-body simulations, which are mutually consistent. Contrary to previous claims that only a `first infall’ is supported by the data, we find an orbital solutionRead More →

The nearby luminous transient AT2018cow: a magnetar formed in a sub-relativistically expanding non-jetted explosion. (arXiv:1911.11912v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Mohan_P/0/1/0/all/0/1">P. Mohan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+An_T/0/1/0/all/0/1">T. An</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yang_J/0/1/0/all/0/1">J. Yang</a> The fast-rising blue optical transient AT2018cow indicated unusual early phase characteristics unlike relatively better studied explosive transients. Its afterglow may be produced by either a relativistically beamed (jetted) or intrinsically luminous (non-jetted) ejecta and carries observational signatures of the progenitor and environment. High resolution monitoring can distinguish between these scenarios and clarify the progenitor nature. We present very long baseline interferometry (VLBI) observations of AT2018cow at 5 GHz involving 21 radio telescopes from the European VLBI Network with five sessionsRead More →

Beyond Limber: Efficient computation of angular power spectra for galaxy clustering and weak lensing. (arXiv:1911.11947v1 [astro-ph.CO]) <a href="http://arxiv.org/find/astro-ph/1/au:+Fang_X/0/1/0/all/0/1">Xiao Fang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Krause_E/0/1/0/all/0/1">Elisabeth Krause</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Eifler_T/0/1/0/all/0/1">Tim Eifler</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+MacCrann_N/0/1/0/all/0/1">Niall MacCrann</a> Angular two-point statistics of large-scale structure observables are important cosmological probes. To reach the high accuracy required by the statistical precision of future surveys, some of these statistics may need to be computed without the commonly employed Limber approximation; the exact computation however requires integration over Bessel functions, and a brute-force evaluation is slow to converge. We present a new method based on our generalized FFTLog algorithm for the efficient computation of angular power spectra beyond theRead More →

OGLE-2016-BLG-1227L: A Wide-separation Planet from a Very Short-timescale Microlensing Event. (arXiv:1911.11953v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Han_C/0/1/0/all/0/1">Cheongho Han</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Udalski_A/0/1/0/all/0/1">Andrzej Udalski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gould_A/0/1/0/all/0/1">Andrew Gould</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Albrow_M/0/1/0/all/0/1">Michael D. Albrow</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chung_S/0/1/0/all/0/1">Sun-Ju Chung</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hwang_K/0/1/0/all/0/1">Kyu-Ha Hwang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jung_Y/0/1/0/all/0/1">Youn Kil Jung</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lee_C/0/1/0/all/0/1">Chung-Uk Lee</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ryu_Y/0/1/0/all/0/1">Yoon-Hyun Ryu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shin_I/0/1/0/all/0/1">In-Gu Shin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shvartzvald_Y/0/1/0/all/0/1">Yossi Shvartzvald</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yee_J/0/1/0/all/0/1">Jennifer C. Yee</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zang_W/0/1/0/all/0/1">Weicheng Zang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cha_S/0/1/0/all/0/1">Sang-Mok Cha</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kim_D/0/1/0/all/0/1">Dong-Jin Kim</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kim_H/0/1/0/all/0/1">Hyoun-Woo Kim</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kim_S/0/1/0/all/0/1">Seung-Lee Kim</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lee_D/0/1/0/all/0/1">Dong-Joo Lee</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lee_Y/0/1/0/all/0/1">Yongseok Lee</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Park_B/0/1/0/all/0/1">Byeong-Gon Park</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pogge_R/0/1/0/all/0/1">Richard W. Pogge</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jee_M/0/1/0/all/0/1">M. James Jee</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kim_D/0/1/0/all/0/1">Doeon Kim</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kim_C/0/1/0/all/0/1">Chun-Hwey Kim</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kim_W/0/1/0/all/0/1">Woong-Tae Kim</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mroz_P/0/1/0/all/0/1">Przemek Mr&#xf3;z</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Szymanski_M/0/1/0/all/0/1">Micha&#x142; K. Szyma&#x144;ski</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Skowron_J/0/1/0/all/0/1">Jan Skowron</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Poleski_R/0/1/0/all/0/1">Radek Poleski</a>,Read More →

The Pan-Pacific Planet Search. VIII. Complete results and the occurrence rate of planets around low-luminosity giants. (arXiv:1911.11954v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Wittenmyer_R/0/1/0/all/0/1">Robert A. Wittenmyer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Butler_R/0/1/0/all/0/1">R.P. Butler</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Horner_J/0/1/0/all/0/1">Jonathan Horner</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Clark_J/0/1/0/all/0/1">Jake Clark</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tinney_C/0/1/0/all/0/1">C.G. Tinney</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Carter_B/0/1/0/all/0/1">B.D. Carter</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_L/0/1/0/all/0/1">Liang Wang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Johnson_J/0/1/0/all/0/1">John Asher Johnson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Collins_M/0/1/0/all/0/1">Michaela Collins</a> Our knowledge of the populations and occurrence rates of planets orbiting evolved intermediate-mass stars lags behind that for solar-type stars by at least a decade. Some radial velocity surveys have targeted these low-luminosity giant stars, providing some insights into the properties of their planetary systems. Here we present the final data release of the Pan-Pacific Planet Search, aRead More →

Characterising the Structure of Halo Merger Trees Using a Single Parameter: The Tree Entropy. (arXiv:1911.11959v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Obreschkow_D/0/1/0/all/0/1">Danail Obreschkow</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Elahi_P/0/1/0/all/0/1">Pascal J. Elahi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lagos_C/0/1/0/all/0/1">Claudia del P. Lagos</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Poulton_R/0/1/0/all/0/1">Rhys J. J. Poulton</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ludlow_A/0/1/0/all/0/1">Aaron D. Ludlow</a> Linking the properties of galaxies to the assembly history of their dark matter haloes is a central aim of galaxy evolution theory. This paper introduces a dimensionless parameter $sin[0,1]$, the “tree entropy”, to parametrise the geometry of a halo’s entire mass assembly hierarchy, building on a generalisation of Shannon’s information entropy. By construction, the minimum entropy ($s=0$) corresponds to smoothly assembled haloes without any mergers. In contrast, theRead More →

Inclination Dependence of The Time-Lag — Photon-Index Correlation in BHXRBs and its Explanation with a Simple Jet Model. (arXiv:1911.11975v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Kylafis_N/0/1/0/all/0/1">N. Kylafis</a> (Univ of Crete, Inst. of Astrophysics-FORTH), <a href="http://arxiv.org/find/astro-ph/1/au:+Reig_P/0/1/0/all/0/1">P. Reig</a> (Inst. of Astrophysics-FORTH, Univ of Crete) Recently, we reported an observational correlation between a) the time-lag of the hard (9 – 15 keV) with respect to the soft (2 – 5 keV) X-ray photons in black-hole X-ray binaries (BHXRBs) and b) the power-law photon index $Gamma$ of the X-ray spectrum. This was physically explained with a simple jet model, i.e., a model where the Comptonization (the Compton upscattering of soft photons) happens inRead More →