RAS_WEB (Page 4,069)

Foreground-immune CMB lensing with shear-only reconstruction. (arXiv:1804.06403v2 [astro-ph.CO] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Schaan_E/0/1/0/all/0/1">Emmanuel Schaan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ferraro_S/0/1/0/all/0/1">Simone Ferraro</a> CMB lensing from current and upcoming wide-field CMB experiments such as AdvACT, SPT-3G and Simons Observatory relies heavily on temperature (vs. polarization). In this regime, foreground contamination to the temperature map produces significant lensing biases, which cannot be fully controlled by multi-frequency component separation, masking or bias hardening. In this letter, we split the standard CMB lensing quadratic estimator into a new set of optimal “multipole” estimators. On large scales, these multipole estimators reduce to the known magnification and shear estimators, and a new shear B-mode estimator. We leverage theRead More →

Modelling the structure of star clusters with fractional Brownian motion. (arXiv:1804.06844v4 [astro-ph.GA] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Lomax_O/0/1/0/all/0/1">O. Lomax</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bates_M/0/1/0/all/0/1">M. L. Bates</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Whitworth_A/0/1/0/all/0/1">A. P. Whitworth</a> The degree of fractal substructure in molecular clouds can be quantified by comparing them with Fractional Brownian Motion (FBM) surfaces or volumes. These fields are self-similar over all length scales and characterised by a drift exponent $H$, which describes the structural roughness. Given that the structure of molecular clouds and the initial structure of star clusters are almost certainly linked, it would be advantageous to also apply this analysis to clusters. Currently, the structure of star clusters is often quantified byRead More →

The Lyman Continuum Escape Survey: Ionizing Radiation from [O III]-Strong Sources at a Redshift of 3.1. (arXiv:1806.01741v2 [astro-ph.GA] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Fletcher_T/0/1/0/all/0/1">Thomas J. Fletcher</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tang_M/0/1/0/all/0/1">Mengtao Tang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Robertson_B/0/1/0/all/0/1">Brant E. Robertson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nakajima_K/0/1/0/all/0/1">Kimihiko Nakajima</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ellis_R/0/1/0/all/0/1">Richard S. Ellis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stark_D/0/1/0/all/0/1">Daniel P. Stark</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Inoue_A/0/1/0/all/0/1">Akio Inoue</a> We present results from the LymAn Continuum Escape Survey (LACES), a Hubble Space Telescope (HST) program designed to characterize the ionizing radiation emerging from a sample of Lyman alpha emitting galaxies at redshift $zsimeq 3.1$. As many show intense [O III] emission characteristic of $z>6.5$ star-forming galaxies, they may represent valuable low redshift analogs of galaxies in the reionization era. UsingRead More →

K2-295 b and K2-237 b: two transiting hot Jupiters. (arXiv:1807.05865v2 [astro-ph.EP] UPDATED) <a href="http://arxiv.org/find/astro-ph/1/au:+Smith_A/0/1/0/all/0/1">A. M. S. Smith</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Csizmadia_S/0/1/0/all/0/1">Sz. Csizmadia</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gandolfi_D/0/1/0/all/0/1">D. Gandolfi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Albrecht_S/0/1/0/all/0/1">S. Albrecht</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Alonso_R/0/1/0/all/0/1">R. Alonso</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Barragan_O/0/1/0/all/0/1">O. Barrag&#xe1;n</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cabrera_J/0/1/0/all/0/1">J. Cabrera</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cochran_W/0/1/0/all/0/1">W. D. Cochran</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dai_F/0/1/0/all/0/1">F. Dai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Deeg_H/0/1/0/all/0/1">H. Deeg</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Eigmuller_P/0/1/0/all/0/1">Ph. Eigm&#xfc;ller</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Endl_M/0/1/0/all/0/1">M. Endl</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Erikson_A/0/1/0/all/0/1">A. Erikson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fridlund_M/0/1/0/all/0/1">M. Fridlund</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fukui_A/0/1/0/all/0/1">A. Fukui</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Grziwa_S/0/1/0/all/0/1">S. Grziwa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Guenther_E/0/1/0/all/0/1">E. W. Guenther</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hatzes_A/0/1/0/all/0/1">A. P. Hatzes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hidalgo_D/0/1/0/all/0/1">D. Hidalgo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hirano_T/0/1/0/all/0/1">T. Hirano</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Korth_J/0/1/0/all/0/1">J. Korth</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kuzuhara_M/0/1/0/all/0/1">M. Kuzuhara</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Livingston_J/0/1/0/all/0/1">J. Livingston</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Narita_N/0/1/0/all/0/1">N. Narita</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nespral_D/0/1/0/all/0/1">D. Nespral</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Niraula_P/0/1/0/all/0/1">P. Niraula</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nowak_G/0/1/0/all/0/1">G. Nowak</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Palle_E/0/1/0/all/0/1">E. Palle</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Patzold_M/0/1/0/all/0/1">M. P&#xe4;tzold</a>, <aRead More →

How Do Galaxies trace a large scale structure?: A case study around a massive protocluster at $z=3.13$. (arXiv:1905.06337v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Shi_K/0/1/0/all/0/1">Ke Shi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Huang_Y/0/1/0/all/0/1">Yun Huang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lee_K/0/1/0/all/0/1">Kyoung-Soo Lee</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Toshikawa_J/0/1/0/all/0/1">Jun Toshikawa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bowen_K/0/1/0/all/0/1">Kathryn N. Bowen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Malavasi_N/0/1/0/all/0/1">Nicola Malavasi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lemaux_B/0/1/0/all/0/1">B. C. Lemaux</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cucciati_O/0/1/0/all/0/1">Olga Cucciati</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fevre_O/0/1/0/all/0/1">Olivier Le Fevre</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dey_A/0/1/0/all/0/1">Arjun Dey</a> In the hierarchical theory of galaxy formation, a galaxy overdensity is a hallmark of a massive cosmic structure. However, it is less well understood how different types of galaxies trace the underlying large-scale structure. Motivated by the discovery of a z=3.13 protocluster, we examine how the same structure is populated by Ly$alpha$-emitting galaxiesRead More →

On the formation of density filaments in the turbulent interstellar medium. (arXiv:1905.06341v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Xu_S/0/1/0/all/0/1">Siyao Xu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ji_S/0/1/0/all/0/1">Suoqing Ji</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lazarian_A/0/1/0/all/0/1">A. Lazarian</a> This study is motivated by recent observations on ubiquitous interstellar density filaments and guided by modern theories of compressible magnetohydrodynamic (MHD) turbulence. The interstellar turbulence shapes the observed density structures. As the fundamental dynamics of compressible MHD turbulence, perpendicular turbulent mixing of density fluctuations entails elongated density structures aligned with the local magnetic field, accounting for low-density parallel filaments seen in diffuse atomic and molecular gas. The elongation of low-density parallel filaments depends on the turbulence anisotropy. When taking into account the partialRead More →

Nuclear Dominated Accretion Flows in Two Dimensions. II. Ejecta dynamics and nucleosynthesis for CO and ONe white dwarfs. (arXiv:1905.06343v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Fernandez_R/0/1/0/all/0/1">Rodrigo Fern&#xe1;ndez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Margalit_B/0/1/0/all/0/1">Ben Margalit</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Metzger_B/0/1/0/all/0/1">Brian D. Metzger</a> We study mass ejection from accretion disks formed in the merger of a white dwarf with a neutron star or black hole. These disks are mostly radiatively-inefficient and support nuclear fusion reactions, with ensuing outflows and electromagnetic transients. Here we perform time-dependent, axisymmetric hydrodynamic simulations of these disks including a physical equation of state, viscous angular momentum transport, a coupled $19$-isotope nuclear network, and self-gravity. We find no detonations in any of the configurations studied.Read More →

Planetary Nebulae and How to Find Them: Color Identification in Big Broadband Surveys. (arXiv:1905.06347v1 [astro-ph.SR]) <a href="http://arxiv.org/find/astro-ph/1/au:+Vejar_G/0/1/0/all/0/1">George Vejar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Montez_R/0/1/0/all/0/1">Rodolfo Montez Jr.</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Morris_M/0/1/0/all/0/1">Margaret Morris</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stassun_K/0/1/0/all/0/1">Keivan G. Stassun</a> Planetary nebulae (PNe) provide tests of stellar evolution, can serve as tracers of chemical evolution in the Milky Way and other galaxies, and are also used as a calibrator of the cosmological distance ladder. Current and upcoming large scale photometric surveys have the potential to complete the census of PNe in our galaxy and beyond, but it is a challenge to disambiguate partially or fully unresolved PNe from the myriad other sources observed in these surveys.Read More →

Direct Detection of Strongly Interacting Sub-GeV Dark Matter via Electron Recoils. (arXiv:1905.06348v1 [hep-ph]) <a href="http://arxiv.org/find/hep-ph/1/au:+Emken_T/0/1/0/all/0/1">Timon Emken</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Essig_R/0/1/0/all/0/1">Rouven Essig</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Kouvaris_C/0/1/0/all/0/1">Chris Kouvaris</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Sholapurkar_M/0/1/0/all/0/1">Mukul Sholapurkar</a> We consider direct-detection searches for sub-GeV dark matter via electron scatterings in the presence of large interactions between dark and ordinary matter. Scatterings both on electrons and nuclei in the Earth’s crust, atmosphere, and shielding material attenuate the expected local dark matter flux at a terrestrial detector, so that such experiments lose sensitivity to dark matter above some critical cross section. We study various models, including dark matter interacting with a heavy and ultralight dark photon, through an electric dipoleRead More →

Dynamical friction in slab geometries and accretion disks. (arXiv:1905.06353v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Vicente_R/0/1/0/all/0/1">Rodrigo Vicente</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cardoso_V/0/1/0/all/0/1">Vitor Cardoso</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zilhao_M/0/1/0/all/0/1">Miguel Zilh&#xe3;o</a> The evolution of planets, stars and even galaxies is driven, to a large extent, by dynamical friction of gravitational origin. There is now a good understanding of the friction produced by extended media, either collisionless of fluid-like. However, the physics of accretion or protoplanetary disks, for instance, is described by slab-like geometries instead, compact in one spatial direction. Here, we find, for the first time, the gravitational wake due to a massive perturber moving through a slab-like medium, describing e.g. accretion disks with sharp transitions. WeRead More →

The Case for a Large-Scale Occultation Network. (arXiv:1905.06354v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Rice_M/0/1/0/all/0/1">Malena Rice</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Laughlin_G/0/1/0/all/0/1">Gregory Laughlin</a> We discuss the feasibility of and present initial designs and approximate cost estimates for a large ($Nsim2000$) network of small photometric telescopes that is purpose-built to monitor $V lesssim 15$ Gaia Mission program stars for occultations by minor solar system bodies. The implementation of this network would permit measurement of the solar system’s tidal gravity field to high precision, thereby revealing the existence of distant trans-Neptunian objects such as the proposed “Planet Nine.” As a detailed example of the network capabilities, we investigate how occultations by Jovian Trojans can beRead More →

Catching butterflies in the sky: Extended catalog of winged or X-shaped radio sources from the latest FIRST data release. (arXiv:1905.06356v1 [astro-ph.HE]) <a href="http://arxiv.org/find/astro-ph/1/au:+Yang_X/0/1/0/all/0/1">Xiaolong Yang</a> (KIAA-PKU), <a href="http://arxiv.org/find/astro-ph/1/au:+Joshi_R/0/1/0/all/0/1">Ravi Joshi</a> (KIAA-PKU), <a href="http://arxiv.org/find/astro-ph/1/au:+Gopal-Krishna/0/1/0/all/0/1">Gopal-Krishna</a> (ARIES), <a href="http://arxiv.org/find/astro-ph/1/au:+An_T/0/1/0/all/0/1">Tao An</a> (SHAO), <a href="http://arxiv.org/find/astro-ph/1/au:+Ho_L/0/1/0/all/0/1">Luis C. Ho</a> (KIAA-PKU), <a href="http://arxiv.org/find/astro-ph/1/au:+Wiita_P/0/1/0/all/0/1">Paul J. Wiita</a> (TCNJ), <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_X/0/1/0/all/0/1">Xiang Liu</a> (XAO), <a href="http://arxiv.org/find/astro-ph/1/au:+Yang_J/0/1/0/all/0/1">Jun Yang</a> (OSO), <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_R/0/1/0/all/0/1">Ran Wang</a> (KIAA-PKU), <a href="http://arxiv.org/find/astro-ph/1/au:+Wu_X/0/1/0/all/0/1">Xuebing Wu</a> (KIAA-PKU), <a href="http://arxiv.org/find/astro-ph/1/au:+Yang_X/0/1/0/all/0/1">Xiaofeng Yang</a> (XAO) We present a catalog of 290 `winged’ or X-shaped radio galaxies (XRGs) extracted from the latest (17 Dec. 2014) data release of the `Very Large Array Faint Images of the Radio Sky at Twenty centimeter’ (VLA FIRST survey). WeRead More →

SHARP $-$ VI. Evidence for CO (1$-$0) molecular gas extended on kpc-scales in AGN star forming galaxies at high redshift. (arXiv:1905.06363v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+Spingola_C/0/1/0/all/0/1">C. Spingola</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+McKean_J/0/1/0/all/0/1">J. P. McKean</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vegetti_S/0/1/0/all/0/1">S. Vegetti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Auger_M/0/1/0/all/0/1">M. W. Auger</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Koopmans_L/0/1/0/all/0/1">L. V. E. Koopmans</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fassnacht_C/0/1/0/all/0/1">C. D. Fassnacht</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lagattuta_D/0/1/0/all/0/1">D. J. Lagattuta</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Powell_D/0/1/0/all/0/1">D. Powell</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rizzo_F/0/1/0/all/0/1">F. Rizzo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stacey_H/0/1/0/all/0/1">H. R. Stacey</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sweijen_F/0/1/0/all/0/1">F. Sweijen</a> We present a study of the stellar host galaxy, CO (1$-$0) molecular gas distribution and AGN emission on 50 to 500 pc-scales of the gravitationally lensed dust-obscured AGN MG J0751+2716 and JVAS B1938+666 at redshifts 3.200 and 2.059, respectively. By correcting for theRead More →

VPLanet: The Virtual Planet Simulator. (arXiv:1905.06367v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Barnes_R/0/1/0/all/0/1">Rory Barnes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Luger_R/0/1/0/all/0/1">Rodrigo Luger</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Deitrick_R/0/1/0/all/0/1">Russell Deitrick</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Driscoll_P/0/1/0/all/0/1">Peter Driscoll</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Quinn_T/0/1/0/all/0/1">Thomas R. Quinn</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fleming_D/0/1/0/all/0/1">David P. Fleming</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Smotherman_H/0/1/0/all/0/1">Hayden Smotherman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+McDonald_D/0/1/0/all/0/1">Diego V. McDonald</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wilhelm_C/0/1/0/all/0/1">Caitlyn Wilhelm</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Garcia_R/0/1/0/all/0/1">Rodolfo Garcia</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Barth_P/0/1/0/all/0/1">Patrick Barth</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Guyer_B/0/1/0/all/0/1">Benjamin Guyer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Meadows_V/0/1/0/all/0/1">Victoria S. Meadows</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bitz_C/0/1/0/all/0/1">Cecilia M. Bitz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gupta_P/0/1/0/all/0/1">Pramod Gupta</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Domagal_Goldman_S/0/1/0/all/0/1">Shawn D. Domagal-Goldman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Armstrong_J/0/1/0/all/0/1">John Armstrong</a> We describe a software package called VPLanet that simulates fundamental aspects of planetary system evolution over Gyr timescales, with a focus on investigating habitable worlds. In this first version, eleven physics modules are included that model internal, atmospheric, rotational, orbital, stellar,Read More →

Evidence for a circumplanetary disc around protoplanet PDS 70 b. (arXiv:1905.06370v1 [astro-ph.EP]) <a href="http://arxiv.org/find/astro-ph/1/au:+Christiaens_V/0/1/0/all/0/1">V. Christiaens</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cantalloube_F/0/1/0/all/0/1">F. Cantalloube</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Casassus_S/0/1/0/all/0/1">S. Casassus</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Price_D/0/1/0/all/0/1">D. J. Price</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Absil_O/0/1/0/all/0/1">O. Absil</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pinte_C/0/1/0/all/0/1">C. Pinte</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Girard_J/0/1/0/all/0/1">J. Girard</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Montesinos_M/0/1/0/all/0/1">M. Montesinos</a> We present the first observational evidence for a circumplanetary disc around the protoplanet PDS~70~b, based on a new spectrum in the $K$ band acquired with VLT/SINFONI. We tested three hypotheses to explain the spectrum: Atmospheric emission from the planet with either (1) a single value of extinction or (2) variable extinction, and (3) a combined atmospheric and circumplanetary disc model. Goodness-of-fit indicators favour the third option, suggesting circumplanetaryRead More →

Low X-Ray Luminosity Galaxy Clusters. IV. SDSS galaxy clusters at z < 0.2. (arXiv:1905.06410v1 [astro-ph.GA]) <a href="http://arxiv.org/find/astro-ph/1/au:+OMill_A/0/1/0/all/0/1">A.L. O&#x27;Mill</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Alonso_M/0/1/0/all/0/1">M.V. Alonso</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Valotto_C/0/1/0/all/0/1">C. Valotto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Castellon_J/0/1/0/all/0/1">J.L. Nilo Castell&#xf3;n</a> This is the fourth of a series of papers on low X-ray luminosity galaxy clusters. The sample comprises 45 galaxy clusters with X-ray luminosities fainter than 0.7 10$^{44}$ erg s$^{-1}$ at redshifts lower than 0.2 in the regions of the Sloan Digital Sky Survey. The sample of spectroscopic members of the galaxy clusters was obtained with the criteria: r$_p$ $le$ 1 Mpc and $Delta V leq sigma$ using our $sigma$ estimates containing 21 galaxy clusters with moreRead More →