By:
On:
In: News, RSSfeeds, Universe Today

The Destruction of Dark Matter isn’t Causing Extra Radiation at the Core of the Milky Way While recent studies suggest that dark matter interactions might create gamma rays, a new study of gamma rays in our galaxy throws shade on that idea. The post The Destruction of Dark Matter isn’t Causing Extra Radiation at the Core of the Milky Way appeared first on Universe Today. Universe Today Go to SourceRead More →

By:
On:
In: News, RSSfeeds, Universe Today

This is the View You Get Staring out of the Space Station’s Cupola Module Those lucky few who have the incredible opportunity to see the Earth from space often report the view gives them a sense of awe, unity and clarity. This perspective-altering experience has come to be known as the Overview Effect, from a book by the same name published 1987 by space philosopher Frank White. In the … Continue reading “This is the View You Get Staring out of the Space Station’s Cupola Module” The post This is the View You Get Staring out of the Space Station’s Cupola Module appeared first onRead More →

By:
On:
In: News, RSSfeeds

Starspots: Revving up the variability of solar-like stars In cosmic comparison, the Sun is a bore. While the brightness of some other stars with similar characteristics fluctuates strongly, the Sun’s variations are much more moderate. Scientists from the Max Planck Institute for Solar System Research (MPS) in Germany, from the Turkish-German University and Boğaziçi University in Turkey, and from Kyung Hee University in South Korea, have now investigated how exactly sun- and starspots affect this behavior. In addition to the number and size of the spots, their distribution plays a crucial role. If groups of sunspots were to appear more frequently clumped together in so-calledRead More →

By:
On:
In: News, RSSfeeds

Astrophysicists prove that dust particles in space are mixed with ice The matter between the stars in a galaxy—called the interstellar medium—consists not only of gas, but also of a great deal of dust. At some point in time, stars and planets originated in such an environment, because the dust particles can clump together and merge into celestial bodies. Important chemical processes also take place on these particles, from which complex organic—possibly even prebiotic—molecules emerge. phys.org Go to SourceRead More →

By:
On:
In: News, RSSfeeds

NASA’s OSIRIS-REx to asteroid Bennu: ‘You’ve got a little Vesta on you’ In an interplanetary faux pas, it appears some pieces of asteroid Vesta ended up on asteroid Bennu, according to observations from NASA’s OSIRIS-REx spacecraft. The new result sheds light on the intricate orbital dance of asteroids and on the violent origin of Bennu, which is a “rubble pile” asteroid that coalesced from the fragments of a massive collision. phys.org Go to SourceRead More →

By:
On:
In: News, RSSfeeds

Study investigates the nature of X-ray binary IGR J18214-1318 Using various space observatories, Italian astronomers have investigated an X-ray binary source known as IGR J18214-1318. Results of the study, detailed in a paper published September 14 on the arXiv pre-print server, provide important information about the properties of this system, shedding more light into its nature. phys.org Go to SourceRead More →

By:
On:
In: arXiv

SMART: A new implementation of Schwarzschild’s Orbit Superposition technique for triaxial galaxies and its application to an N-body merger simulation. (arXiv:2009.08979v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Neureiter_B/0/1/0/all/0/1">Bianca Neureiter</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Thomas_J/0/1/0/all/0/1">Jens Thomas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Saglia_R/0/1/0/all/0/1">Roberto Saglia</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bender_R/0/1/0/all/0/1">Ralf Bender</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Finozzi_F/0/1/0/all/0/1">Fabrizio Finozzi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Krukau_A/0/1/0/all/0/1">Aliaksei Krukau</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Naab_T/0/1/0/all/0/1">Thorsten Naab</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rantala_A/0/1/0/all/0/1">Antti Rantala</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Frigo_M/0/1/0/all/0/1">Matteo Frigo</a> We present SMART, a new 3D implementation of the Schwarzschild Method and its application to a triaxial N-body merger simulation. SMART fits full line-of-sight velocity distributions (LOSVDs) to determine the viewing angles, black hole, stellar and dark matter (DM) masses and the stellar orbit distribution of galaxies. Our model uses a 5D orbital starting space toRead More →

By:
On:
In: arXiv

Neural-Network Assisted Study of Nitrogen Atom Dynamics on Amorphous Solid Water. I. Adsorption & Desorption. (arXiv:2009.09994v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Molpeceres_G/0/1/0/all/0/1">Germ&#xe1;n Molpeceres</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zaverkin_V/0/1/0/all/0/1">Viktor Zaverkin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kastner_J/0/1/0/all/0/1">Johannes K&#xe4;stner</a> Dynamics of adsorption and desorption of (4S)-N on amorphous solid water are analyzed using molecular dynamics simulations. The underlying potential energy surface was provided by machine-learned interatomic potentials. Binding energies confirm the latest available theoretical and experimental results. The nitrogen sticking coefficient is close to unity at dust temperatures of 10 K but decreases at higher temperatures. We estimate a desorption time scale of 1 {mu}s at 28 K. The estimated time scale allows chemical processes mediated by diffusionRead More →

By:
On:
In: arXiv

Local gravity test of unified models of inflation and dark energy in $f(R)$ gravity. (arXiv:2004.00864v3 [astro-ph.CO] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Yashiki_M/0/1/0/all/0/1">Mai Yashiki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sakai_N/0/1/0/all/0/1">Nobuyuki Sakai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Saito_R/0/1/0/all/0/1">Ryo Saito</a> We consider $f(R)$ gravity theories which unify $R^n$ inflation and dark energy models. First, from the final Planck data of the cosmic microwave background, we obtain a condition, $1.977 < n < 2.003$. Next, under this constraint, we investigate local-gravity tests for three models. We find that the $R^n$ term can dominate over the dark energy term even at the Earth’s curvature scale, contrary to intuition; however, the $R^n$ term does not relax or tighten the constraints on theRead More →

By:
On:
In: arXiv

Palatini quadratic gravity: spontaneous breaking of gauged scale symmetry and inflation. (arXiv:2003.08516v4 [hep-th] UPDATED) <a href="http://arxiv.org/find/hep-th/1/au:+Ghilencea_D/0/1/0/all/0/1">D. M. Ghilencea</a> We study quadratic gravity $R^2+R_{[munu]}^2$ in the Palatini formalism where the connection and the metric are independent. This action has a {it gauged} scale symmetry (also known as Weyl gauge symmetry) of Weyl gauge field $v_mu= (tildeGamma_mu-Gamma_mu)/2$, with $tildeGamma_mu$ ($Gamma_mu$) the trace of the Palatini (Levi-Civita) connection, respectively. The underlying geometry is non-metric due to the $R_{[munu]}^2$ term acting as a gauge kinetic term for $v_mu$. We show that the gauge field becomes massive by a gravitational Stueckelberg mechanism by absorbing the derivative of the dilaton ($partial_mulnphi$).Read More →

By:
On:
In: arXiv

Uptunneling to de Sitter. (arXiv:2003.05460v2 [hep-th] UPDATED) <a href="http://arxiv.org/find/hep-th/1/au:+Mirbabayi_M/0/1/0/all/0/1">Mehrdad Mirbabayi</a> We propose a Euclidean preparation of an asymptotically AdS$_2$ spacetime that contains an inflating dS$_2$ bubble. The setup can be embedded in a four dimensional theory with a Minkowski vacuum and a false vacuum. AdS$_2$ times 2-sphere approximate the near horizon geometry of a $4d$ near-extremal RN wormhole. Likewise, in the false vacuum the near-horizon geometry of a near-extremal black hole is approximately dS$_2$ times 2-sphere. We interpret the Euclidean solution as describing the decay of an excitation inside the wormhole to a false vacuum bubble. The result is an inflating region inside a non-traversableRead More →

By:
On:
In: arXiv

Compensated Isocurvature Perturbations in the Galaxy Power Spectrum. (arXiv:2002.12931v2 [astro-ph.CO] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Barreira_A/0/1/0/all/0/1">Alexandre Barreira</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cabass_G/0/1/0/all/0/1">Giovanni Cabass</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lozanov_K/0/1/0/all/0/1">Kaloian D. Lozanov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schmidt_F/0/1/0/all/0/1">Fabian Schmidt</a> We investigate the potential of the galaxy power spectrum to constrain compensated isocurvature perturbations (CIPs), primordial fluctuations in the baryon density that are compensated by fluctuations in CDM density to ensure an unperturbed total matter density. We show that CIPs contribute to the galaxy overdensity at linear order, and if they are close to scale-invariant, their effects are nearly perfectly degenerate with the local PNG parameter $f_{rm nl}$ if they correlate with the adiabatic perturbations. This degeneracy can however be brokenRead More →

By:
On:
In: arXiv

The ALMA view of the high-redshift relation between supermassive black holes and their host galaxies. (arXiv:2002.00958v2 [astro-ph.GA] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Pensabene_A/0/1/0/all/0/1">A. Pensabene</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Carniani_S/0/1/0/all/0/1">S. Carniani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Perna_M/0/1/0/all/0/1">M. Perna</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cresci_G/0/1/0/all/0/1">G. Cresci</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Decarli_R/0/1/0/all/0/1">R. Decarli</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Maiolino_R/0/1/0/all/0/1">R. Maiolino</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Marconi_A/0/1/0/all/0/1">A. Marconi</a> This work aims at studying the $M_{BH}-M_{dyn}$ relation of a sample of $2<z<7$ quasars by constraining their host galaxy masses through full kinematical modeling of the cold gas kinematics, thus avoiding all possible biases and effects introduced by the rough virial estimates usually adopted so far. For this purpose we retrieved public observations of $72$ quasar host galaxies observed in ${rm [CII]_{158mu m}}$ or ${rm CO}$Read More →

By:
On:
In: arXiv

Homogeneity in the early chemical evolution of the Sextans dwarf Spheroidal galaxy. (arXiv:2001.11033v2 [astro-ph.GA] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Lucchesi_R/0/1/0/all/0/1">R. Lucchesi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lardo_C/0/1/0/all/0/1">C. Lardo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Primas_F/0/1/0/all/0/1">F. Primas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jablonka_P/0/1/0/all/0/1">P. Jablonka</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+North_P/0/1/0/all/0/1">P. North</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Battaglia_G/0/1/0/all/0/1">G. Battaglia</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Starkenburg_E/0/1/0/all/0/1">E. Starkenburg</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hill_V/0/1/0/all/0/1">V. Hill</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Irwin_M/0/1/0/all/0/1">M. Irwin</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Francois_P/0/1/0/all/0/1">P. Francois</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shetrone_M/0/1/0/all/0/1">M. Shetrone</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tolstoy_E/0/1/0/all/0/1">E. Tolstoy</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Venn_K/0/1/0/all/0/1">K. Venn</a> We present the high-resolution spectroscopic analysis of two new extremely metal-poor stars (EMPS) candidates in the dwarf spheroidal galaxy Sextans. These targets were pre-selected from medium resolution spectra centered around the Ca II triplet in the near-infrared and followed-up at higher resolution with VLT/UVES. We confirm their low metallicities with [Fe/H]=-2.95Read More →

By:
On:
In: arXiv

Properties of central stars of planetary nebulae with distances in Gaia DR2. (arXiv:1909.04601v4 [astro-ph.SR] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Gonzalez_Santamaria_I/0/1/0/all/0/1">I. Gonz&#xe1;lez-Santamar&#xed;a</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Manteiga_M/0/1/0/all/0/1">M. Manteiga</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Manchado_A/0/1/0/all/0/1">A. Manchado</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ulla_A/0/1/0/all/0/1">A. Ulla</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dafonte_C/0/1/0/all/0/1">C. Dafonte</a> Context. We have compiled a catalogue of central stars of planetary nebulae (CSPN) with reliable distances and positions obtained from Gaia Data Release 2 (DR2) astrometry. Distances derived from parallaxes allow us to analyse the galactic distribution and estimate other parameters such as sizes, kinematical ages, bolometric magnitudes, and luminosities. Aims. Our objective is to analyse the information regarding distances together with other available literature data about photometric properties, nebular kinematics, and stellar effective temperaturesRead More →

By:
On:
In: arXiv

IDEAS: Immersive Dome Experiences for Accelerating Science. (arXiv:1907.05383v2 [astro-ph.IM] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Faherty_J/0/1/0/all/0/1">Jacqueline K. Faherty</a> (American Museum of Natural History Hayden Planetarium), <a href="http://arxiv.org/find/astro-ph/1/au:+SubbaRao_M/0/1/0/all/0/1">Mark SubbaRao</a> (Adler Planetarium, International Planetarium Society), <a href="http://arxiv.org/find/astro-ph/1/au:+Wyatt_R/0/1/0/all/0/1">Ryan Wyatt</a> (California Academy of Sciences), <a href="http://arxiv.org/find/astro-ph/1/au:+Ynnerman_A/0/1/0/all/0/1">Anders Ynnerman</a> (Link&#xf6;ping University), <a href="http://arxiv.org/find/astro-ph/1/au:+Tyson_N/0/1/0/all/0/1">Neil deGrasse Tyson</a> (American Museum of Natural History Hayden Planetarium), <a href="http://arxiv.org/find/astro-ph/1/au:+Geller_A/0/1/0/all/0/1">Aaron Geller</a> (Adler Planetarium Northwestern University), <a href="http://arxiv.org/find/astro-ph/1/au:+Weber_M/0/1/0/all/0/1">Maria Weber</a> (Adler Planetarium University of Chicago Delta State University), <a href="http://arxiv.org/find/astro-ph/1/au:+Rosenfield_P/0/1/0/all/0/1">Philip Rosenfield</a> (AAS WorldWide Telescope), <a href="http://arxiv.org/find/astro-ph/1/au:+Steffen_W/0/1/0/all/0/1">Wolfgang Steffen</a> (Instituto de Astronom&#xed;a UNAM), <a href="http://arxiv.org/find/astro-ph/1/au:+Stoeckle_G/0/1/0/all/0/1">Gabriel Stoeckle</a> (Natural History Museum Vienna), <a href="http://arxiv.org/find/astro-ph/1/au:+Weiskopf_D/0/1/0/all/0/1">Daniel Weiskopf</a> (Visualization Research Center University of Stuttgart), <a href="http://arxiv.org/find/astro-ph/1/au:+Magnor_M/0/1/0/all/0/1">Marcus Magnor</a> (Computer Graphics LabRead More →

By:
On:
In: arXiv

Multicomponent Dark Matter in the Light of CALET and DAMPE. (arXiv:1905.10136v3 [hep-ph] UPDATED) <a href="http://arxiv.org/find/hep-ph/1/au:+Geng_C/0/1/0/all/0/1">Chao-Qiang Geng</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Huang_D/0/1/0/all/0/1">Da Huang</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Yin_L/0/1/0/all/0/1">Lu Yin</a> In the light of the latest measurements on the total $e^+ + e^-$ flux by CALET and DAMPE experiments, we revisit the multicomponent leptonically decaying dark matter (DM) explanations to the cosmic-ray electron/positron excesses observed previously. Especially, we use the single and double-component DM models to explore the compatibility of the AMS-02 positron fraction with the new CALET or DAMPE data. It turns out that neither single nor double-component DM models are able to fit the AMS-02 positron fraction and DAMPE total $e^+Read More →