Homestead Sports Complex, at 1601 SE 28th Ave., and Roby George Park, at 201 SW 11th Ave., will distribute at most 10 sandbags per Homestead resident on Thursday from 7 a.m. to 7 p.m. Proof of residency is required.Sweetwater Public Works at 1701 NW 110 Ave. for those that show proof of residency. Limited to six bags per household.Second location for Miami Beach sandbag distribution at 79th Street & Collins Avenue for residents who provide ID. Open until 7 p.m. or until sand runs out.Broward County:Copyright 2019 Sunbeam Television Corp. All rights reserved. This material may not be published, broadcast, rewritten or redistributed. (WSVN) – Below is a list of locations to pick up sandbags in preparation for Hurricane Irma in South Florida. This list will be updated as information becomes available.Miami-Dade County:Public Works Yard at 451 Dade Blvd. in Miami Beach and at 5th Street and Ocean Drive on Thursday. For Miami Beach residents with ID. Ten bags allotted per family.North Miami Motor Pool at 1855 NE 142nd St. on from 8 a.m. to 5 p.m. while supplies last. For North Miami residents. Six bags per resident.Adonel Concrete at 2101 NW 110th Ave. in Sweetwater Thursday and Friday from 4 p.m. to 8 p.m. Bring your own bags to fill sand.For residents that bring their own sandbags and shovels beginning on Thursday at 8:30 a.m., sand will be available at these locations in District 9:Goulds Park at 11350 SW 216th St.Country Star/Cambridge Estates at 28350 SW 136th PlaceLas Palmas at Krome Avenue and 200th StreetSouth Miami Heights/Oak Park (Roberta Hunter Park) at Southwest 117th Avenue and Southwest 208th StreetSerena Lakes Park at 13965 SW 180th StreetEureka Villas Park at 14301 SW 180th Terrace
A VVIP flight of Biman Bangladesh Airlines carrying the prime minister and her entourage left Hazrat Shahjalal International Airport for Kathmandu at 8:05am, reports UNB.The flight landed at Tribhuvan International Airport in Kathmandu at 9:05 am local time (9:20am Bangladesh time).Sheikh Hasina was escorted to Hotel Soaltee Crowne Plaza at Tahachal Marg in Kathmandu by a ceremonial motorcade where she will be staying during her visit.Later in the day, the permier will meet Nepalese president Bidya Devi Bhandari at Sheetal Nibash, the Presidential Palace, in the capital city.She will also attend a luncheon there to be hosted by the Nepalese president.In the afternoon, the Bangladesh prime minister along with other leaders will attend the opening session of the 4th BIMSTEC Summit at Hotel Soaltee Crowne Plaza.In the evening, she will hold a meeting with her Indian counterpart Narendra Modi.Hasina and other leaders will also join a gala dinner to be hosted by Nepalese prime minister KP Sharma Oli in the city’s Hyatt Regency Hotel in the evening.The prime minister is expected to return home on Friday noon. Prime minister Sheikh Hasina. File PhotoPrime minister Sheikh Hasina reached Kathmandu on a two-day official visit to Nepal to attend the 4th BIMSTEC Summit.The Bay of Bengal Initiative for Multi-Sectoral Technical and Economic Cooperation (BIMSTEC) having seven member states — Bangladesh, Bhutan, India, Nepal, Sri Lanka, Myanmar and Thailand — came into being on 6 June 1997 through the Bangkok Declaration.
Artist’s impression of SS 433. Credit: NASA The only known supercritical accretor in the Milky Way galaxy is SS 433, a highly exotic eclipsing binary star system. Its primary object is likely a black hole. Its secondary companion is believed to be a late A-type star based on its light spectrum. The secondary in SS 433 is losing mass into an accretion disk as it spirals in toward the primary, which is slowly consuming it. In turn, as the accretion disc spirals in toward the primary, it becomes super-heated and emits intense X-rays. Physicists are fascinated by the exotic nature of SS 433, but also by its strong resemblance to ultraluminous X-ray sources (ULXs), which are astronomical sources of X-rays that are less luminous than the nuclei of active galaxies, but are more luminous than any known stellar process. These are sources of X-rays that exceed the Eddington luminosities of neutron stars and stellar black holes. Recently, a group of researchers from Russia and Japan have compared the optical spectra of ULXs to SS 433 and have determined that ULXs with X-ray luminosities of ~1040 erg S-1 must constitute a homogenous class of objects that most likely have SCADs. They have published their results in Nature Physics. The most popular models for ULXs have either intermediate mass black holes with standard accretion disks or stellar-mass black holes with accretion disk luminosity exceeding the Eddington limit. Based on X-ray data alone, it is not possible to distinguish these models, so the researchers have turned to optical spectroscopy to find unique information about ULXs. Using the 8.2 meter Subaru Telescope of the National Astronomical Observatory of Japan, located at the Mauna Kea Observatory on Hawaii, they obtained high-quality spectroscopic data from a number of ULX sources.They have determined that ULX spectra are quite similar to late nitrogen Wolf-Rayet stars (WNLs), which exhibit broad emissions of ionized nitrogen and helium or carbon. They have very high surface temperatures and produce intense stellar winds. The spectra from ULXs also resemble those of luminous blue variable stars (LBVs) in the compact stages of stellar development. Because the physical conditions of its disk wind may be similar to WNL stars, SS 433 also bears a strong resemblance to ULXs. The authors write, “Such spectra of high luminosities with prominent He II emission lines have never been observed from any stellar-mass black hole X-ray binaries, except for SS 433 and those having WNL donors [secondaries losing mass to the accretion disks of primaries in binary systems].” They exclude a number of stellar cases, including ULXs with WNL donors that exhibit stellar winds with the observed spectra. Wind terminal velocity is determined by surface gravity, making it difficult to explain the rapid variability of the He II line width in the recorded spectra. The authors conclude that SS 433 is intrinsically the same as ULXs, but is an extreme case with a particularly high mass accretion rate from its secondary, which accounts for the presence of its persistent jet outflows. © 2015 Phys.org Journal information: Nature Physics Explore further More information: “Supercritical accretion disks in ultraluminous X-ray sources and SS 433.” Nature Physics (2015) DOI: 10.1038/nphys3348AbstractThe black hole mass and accretion rate in ultraluminous X-ray sources (ULXs) in external galaxies, whose X-ray luminosities exceed those of the brightest black holes in our Galaxy by hundreds and thousands of times1, 2, is an unsolved problem. Here we report that all ULXs ever spectroscopically observed have almost the same optical spectra, apparently of WNL type (late nitrogen Wolf–Rayet stars) or LBV (luminous blue variables) in their hot state, which are very scarce stellar objects. We show that the spectra do not originate from WNL/LBV-type donors but from very hot winds from the accretion disks with nearly normal hydrogen content, which have similar physical conditions to the stellar winds from these stars. The optical spectra are similar to that of SS 433, the only known supercritical accretor in our Galaxy3, although the ULX spectra indicate a higher wind temperature. Our results suggest that ULXs with X-ray luminosities of ~1040 erg s−1 must constitute a homogeneous class of objects, which most likely have supercritical accretion disks. Ultra-luminous X-ray sources in starburst galaxies (Phys.org)—Many black holes are believed to have surrounding accretion disks of matter trapped by gravity and spiraling toward the event horizon. Supercritical accretion disks (SCADs) are those with mass accretion rates exceeding the Eddington limit—this describes the maximum possible luminosity of an energetic body when the outward force of radiation is in equilibrium with gravitation. Masses that exceed the Eddington luminosity to produce SCADs emit extremely intense stellar winds from their outer layers. Citation: Researchers characterize mysterious ultraluminous X-ray sources (2015, June 9) retrieved 18 August 2019 from https://phys.org/news/2015-06-characterize-mysterious-ultraluminous-x-ray-sources.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.