The Supernova
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Exploring Pulsars
High-energy astrophysics Explore the PUL SAR menagerie Astronomers are discovering many strange properties of compact stellar objects called pulsars. Here’s how they fit together. by Victoria M. Kaspi f you browse through an astronomy book published 25 years ago, you’d likely assume that astronomers understood extremely dense objects called neutron stars fairly well. The spectacular Crab Nebula’s central body has been a “poster child” for these objects for years. This specific neutron star is a pulsar that I rotates roughly 30 times per second, emitting regular appar- ent pulsations in Earth’s direction through a sort of “light- house” effect as the star rotates. While these textbook descriptions aren’t incorrect, research over roughly the past decade has shown that the picture they portray is fundamentally incomplete. Astrono- mers know that the simple scenario where neutron stars are all born “Crab-like” is not true. Experts in the field could not have imagined the variety of neutron stars they’ve recently observed. We’ve found that bizarre objects repre- sent a significant fraction of the neutron star population. With names like magnetars, anomalous X-ray pulsars, soft gamma repeaters, rotating radio transients, and compact Long the pulsar poster child, central objects, these bodies bear properties radically differ- the Crab Nebula’s central object is a fast-spinning neutron star ent from those of the Crab pulsar. Just how large a fraction that emits jets of radiation at its they represent is still hotly debated, but it’s at least 10 per- magnetic axis. Astronomers cent and maybe even the majority. -
BRAS Newsletter August 2013
www.brastro.org August 2013 Next meeting Aug 12th 7:00PM at the HRPO Dark Site Observing Dates: Primary on Aug. 3rd, Secondary on Aug. 10th Photo credit: Saturn taken on 20” OGS + Orion Starshoot - Ben Toman 1 What's in this issue: PRESIDENT'S MESSAGE....................................................................................................................3 NOTES FROM THE VICE PRESIDENT ............................................................................................4 MESSAGE FROM THE HRPO …....................................................................................................5 MONTHLY OBSERVING NOTES ....................................................................................................6 OUTREACH CHAIRPERSON’S NOTES .........................................................................................13 MEMBERSHIP APPLICATION .......................................................................................................14 2 PRESIDENT'S MESSAGE Hi Everyone, I hope you’ve been having a great Summer so far and had luck beating the heat as much as possible. The weather sure hasn’t been cooperative for observing, though! First I have a pretty cool announcement. Thanks to the efforts of club member Walt Cooney, there are 5 newly named asteroids in the sky. (53256) Sinitiere - Named for former BRAS Treasurer Bob Sinitiere (74439) Brenden - Named for founding member Craig Brenden (85878) Guzik - Named for LSU professor T. Greg Guzik (101722) Pursell - Named for founding member Wally Pursell -
Discovery of a Pulsar Wind Nebula Candidate in the Cygnus Loop
Discovery of a Pulsar Wind Nebula Candidate in the Cygnus Loop 2 3 S Satoru Katsuda" Hiroshi Tsunemi , Koji Mori , Hiroyuki Uchida" Robert Petre , Shin'ya 1 Yamada , and Thru Tamagawa' ABSTRACT We report on a discovery of a diffuse nebula containing a pointlike source in the southern blowout region of the Cygnus Loop supernova remnant, based on Suzaku and XMM-Newton observations. The X-ray spectra from the nebula and the pointlike source are well represented by an absorbed power-law model with photon indices of 2.2±0.1 and 1.6±0.2, respectively. The photon indices as well as the flux ratio of F nebula/ F po;.,li" ~ 4 lead us to propose that the system is a pulsar wind nebula, although pulsations have not yet been detected. If we attribute its origin to the Cygnus Loop supernova, then the 0.5- 8 keY luminosity of the nebula is computed to be 2.1xlo"' (d/MOpc)2ergss-" where d is the distance to the Loop. This implies a spin-down loss-energy E ~ 2.6 X 1035 (d/MOpc)2ergss-'. The location of the neutron star candidate, ~2° away from the geometric center of the Loop, implies a high transverse velocity of ~ 1850(8/2D ) (d/540pc) (t/lOkyr)- ' kms-" assuming the currently accepted age of the Cygnus Loop. Subject headings: ISM: individual objects (Cygnus Loop) - ISM: supernova remnants - pulsars: general - stars: neutron - stars: winds, outflows - X-rays: ISM 'RlKEN (The Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako, Sailama 351-0198 2Department of EaTth and Space Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Thyonaka, Osaka, 60-0043, Japan SDepartment of Applied Physics, Faculty of Engineering, University of Miyazaki, 1-1 Gakuen Klbana-dai Nishi, Miyazaki, 889-2192, Japan ' Department of PhysiCS, Kyoto University, Kitashirakawa-oiwake-clto, Sakyo, Kyoto 606-8502, J apan 'NASA Goddard Space Flight Center, Code 662, Greenbelt MD 20771 - 2 - 1. -
Determination of the Night Sky Background Around the Crab Pulsar Using Its Optical Pulsation
28th International Cosmic Ray Conference 2449 Determination of the Night Sky Background around the Crab Pulsar Using its Optical Pulsation E. O˜na-Wilhelmi1,2, J. Cortina3, O.C. de Jager1, V. Fonseca2 for the MAGIC collaboration (1) Unit for Space Physics, Potchefstroom University for CHE, Potchefstroom 2520, South Africa (2) Dept. de f´isica At´omica, Nuclear y Molecular, UCM, Ciudad Universitaria s/n, Madrid, Spain (3) Institut de Fisica de l’Altes Energies, UAB, Barcelona, Spain Abstract The poor angular resolution of imaging γ-ray telescopes is offset by the large collection area of the next generation telescopes such as MAGIC (17 m diameter) which makes the study of optical emission associated with some γ-ray sources feasible. In particular the optical photon flux causes an increase in the photomultiplier DC currents. Furthermore, the extremely fast response of PMs make them ideal detectors for fast (subsecond) optical transients and periodic sources like pulsars. The HEGRA CT1 telescope (1.8 m radius) is the smallest Cerenkovˆ telescope which has seen the Crab optical pulsations. 1. Method Imaging Atmospheric Cerenkovˆ Detectors (IACT) can be used to detect the optical emission of an astronomical object through the increase it generates in the currents of the camera pixels [7,3]. Since the Crab pulsar shows pulsed emission in the optical wavelengths with the same frequency as in radio and most probably of VHE γ-rays, we use the central pixel of CT1 [5] and MAGIC [1] to monitor the optical Crab pulsation. Before the Crab observations were performed, the expected rate of the Crab pulsar and background were estimated theoretically. -
XMM-Newton Observation of the Northeastern Limb of the Cygnus Loop Supernova Remnant
XMM-Newton Observation of the Northeastern Limb of the Cygnus Loop Supernova Remnant Norbert Nemes Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan 04 February 2005 Osaka University Abstract We have observed the northeastern limb of the Cygnus Loop supernova remnant with the XMM-Newton observatory, as part of a 7-pointing campaign to map the remnant across its diameter. We performed medium sensitivity spatially resolved X-ray spectroscopy on the data in the 0.3-3.0 keV energy range, and for the first time we have detected C emission lines in our spectra. The background subtracted spectra were fitted with a single temperature absorbed non-equilibrium (VNEI) model. We created color maps and plotted the radial variation of the different parameters. We found that the heavy element abundances were depleted, but increase toward the edge of the remnant, exhibiting a jump structure near the northeastern edge of the field of view. The depletion suggests that the plasma in this region represents the shock heated ISM rather than the ejecta, while the radial increase of the elemental abundances seems to support the cavity explosion origin. The temperature decreases in the radial direction from 0:3keV to about 0:2keV , however, this ∼ ∼ decrease is not monotonic. There is a low temperature region in the part of the field of view closest to the center of the remnant, which is characterized by low abundances and high NH values. Another low temperature region characterized by low NH values but where the heavy element abundances suddenly jump to high values was found at the northeastern edge of the field of view. -
Pos(MULTIF15)020 Al
Suzaku Highlights of Supernova Remnants PoS(MULTIF15)020 Satoru Katsuda∗† Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), 3-1-1 Yoshinodai, Chuo, Sagamihara, Kanagawa 252-5210, Japan E-mail: [email protected] Hiroshi Tsunemi Department of Earth and Space Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan E-mail: [email protected] Suzaku was the Japanese 5th X-ray astronomy satellite operated from 2005 July 10 to 2015 Au- gust 26. Its key features are high-sensitivity wide-band X-ray spectroscopy available with both the X-ray imaging CCD cameras and the non-imaging collimated hard X-ray detector. A number of interesting scientific discoveries have been achieved in various fields. Among them, I will focus on results on supernova remnants. The topics in this paper include (1) revealing distributions of supernova ejecta, (2) establishing over-ionized plasmas by discoveries of radiative-recombination continua, (3) constraining progenitors of Type Ia SNRs from Mn/Cr and Ni/Fe line ratios, and (4) searching for X-ray counterparts from unidentified HESS sources. These results are of high sci- entific importance in physics of supernova explosions, non-equilibrium plasmas, and cosmic-ray acceleration. XI Multifrequency Behaviour of High Energy Cosmic Sources Workshop, 25-30 May 2015 Palermo, Italy ∗Speaker. †A footnote may follow. © c CopyrightCopyright owned owned by the author(s) under the terms of the Creative Creative Commons License Attribution-NonCommercial 4.0 International. http://pos.sissa.it/ Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0). -
Cassiopeia A: on the Origin of the Hard X-Ray Continuum and the Implication of the Observed O Vııı Ly-Α/Ly-Β Distribution
A&A 365, L225–L230 (2001) Astronomy DOI: 10.1051/0004-6361:20000048 & c ESO 2001 Astrophysics Cassiopeia A: On the origin of the hard X-ray continuum and the implication of the observed O vııı Ly-α/Ly-β distribution J. A. M. Bleeker1, R. Willingale2, K. van der Heyden1, K. Dennerl3,J.S.Kaastra1, B. Aschenbach3, and J. Vink4,5,6 1 SRON National Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands 2 Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH, UK 3 Max-Planck-Institut f¨ur extraterrestrische Physik, Giessenbachstraße, 85740 Garching, Germany 4 Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany 5 Columbia Astrophysics Laboratory, Columbia University, 550 West 120th Street, New York, NY 10027, USA 6 Chandra Fellow Received 6 October 2000 / Accepted 24 October 2000 Abstract. We present the first results on the hard X-ray continuum image (up to 15 keV) of the supernova remnant Cas A measured with the EPIC cameras onboard XMM-Newton. The data indicate that the hard X-ray tail, observed previously, that extends to energies above 100 keV does not originate in localised regions, like the bright X-ray knots and filaments or the primary blast wave, but is spread over the whole remnant with a rather flat hardness ratio of the 8–10 and 10–15 keV energy bands. This result does not support an interpretation of the hard X-radiation as synchrotron emission produced in the primary shock, in which case a limb brightened shell of hard X-ray emission close to the primary shock front is expected. -
Hubble Revisits the Veil Nebula 2 April 2021
Image: Hubble revisits the Veil Nebula 2 April 2021 this stellar violence, the shockwaves and debris from the supernova sculpted the Veil Nebula's delicate tracery of ionized gas—creating a scene of surprising astronomical beauty. The Veil Nebula is also featured in Hubble's Caldwell Catalog, a collection of astronomical objects that have been imaged by Hubble and are visible to amateur astronomers in the night sky. Provided by NASA Credit: ESA/Hubble & NASA, Z. Levay This image taken by the NASA/ESA Hubble Space Telescope revisits the Veil Nebula, which was featured in a previous Hubble image release. In this image, new processing techniques have been applied, bringing out fine details of the nebula's delicate threads and filaments of ionized gas. To create this colorful image, observations were taken by Hubble's Wide Field Camera 3 instrument using five different filters. The new post-processing methods have further enhanced details of emissions from doubly ionized oxygen (seen here in blues), ionized hydrogen, and ionized nitrogen (seen here in reds). The Veil Nebula lies around 2,100 light-years from Earth in the constellation of Cygnus (the Swan), making it a relatively close neighbor in astronomical terms. Only a small portion of the nebula was captured in this image. The Veil Nebula is the visible portion of the nearby Cygnus Loop, a supernova remnant formed roughly 10,000 years ago by the death of a massive star. That star—which was 20 times the mass of the Sun—lived fast and died young, ending its life in a cataclysmic release of energy. -
Reconsidering the Identification of M101 Hypernova Remnant
Reconsidering the Identification of M101 Hypernova Remnant Candidates S. L. Snowden1,2, K. Mukai1,3, and W. Pence4 Code 662, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 and K. D. Kuntz5 Joint Center for Astrophysics, University of Maryland Baltimore County, Baltimore, MD, 21250 ABSTRACT Using a deep Chandra AO-1 observation of the face-on spiral galaxy M101, we examine three of five previously optically-identified X-ray sources which are spatially correlated with optical supernova remnants (MF54, MF57, and MF83). The X-ray fluxes from these objects, if due to diffuse emission from the remnants, are bright enough to require a new class of objects, with the possible attribution by Wang to diffuse emission from hypernova remnants. Of the three, MF83 was considered the most likely candidate for such an object due to its size, nature, and close positional coincidence. However, we find that MF83 is clearly ruled out as a hypernova remnant by both its temporal variability and spectrum. The bright X-ray sources previously associated with MF54 and MF57 are seen by Chandra to be clearly offset from the optical positions of the supernova remnants by several arc seconds, confirming a result suggested by the previous work. MF54 does have a faint X-ray counterpart, however, with a luminosity and temperature consistent with a normal supernova remnant of its size. The most likely classifications of the sources are as X-ray binaries. Although counting statistics are limited, over the 0.3–5.0 keV spectral band the data are well fit by simple absorbed power laws with luminosities in the 1038 − 1039 ergs s−1 range. -
Experiencing Hubble
PRESCOTT ASTRONOMY CLUB PRESENTS EXPERIENCING HUBBLE John Carter August 7, 2019 GET OUT LOOK UP • When Galaxies Collide https://www.youtube.com/watch?v=HP3x7TgvgR8 • How Hubble Images Get Color https://www.youtube.com/watch? time_continue=3&v=WSG0MnmUsEY Experiencing Hubble Sagittarius Star Cloud 1. 12,000 stars 2. ½ percent of full Moon area. 3. Not one star in the image can be seen by the naked eye. 4. Color of star reflects its surface temperature. Eagle Nebula. M 16 1. Messier 16 is a conspicuous region of active star formation, appearing in the constellation Serpens Cauda. This giant cloud of interstellar gas and dust is commonly known as the Eagle Nebula, and has already created a cluster of young stars. The nebula is also referred to the Star Queen Nebula and as IC 4703; the cluster is NGC 6611. With an overall visual magnitude of 6.4, and an apparent diameter of 7', the Eagle Nebula's star cluster is best seen with low power telescopes. The brightest star in the cluster has an apparent magnitude of +8.24, easily visible with good binoculars. A 4" scope reveals about 20 stars in an uneven background of fainter stars and nebulosity; three nebulous concentrations can be glimpsed under good conditions. Under very good conditions, suggestions of dark obscuring matter can be seen to the north of the cluster. In an 8" telescope at low power, M 16 is an impressive object. The nebula extends much farther out, to a diameter of over 30'. It is filled with dark regions and globules, including a peculiar dark column and a luminous rim around the cluster. -
Wind-Blown Bubbles and Hii Regions Around Massive
RevMexAA (Serie de Conferencias), 30, 64{71 (2007) WIND-BLOWN BUBBLES AND HII REGIONS AROUND MASSIVE STARS S. J. Arthur1 RESUMEN La evoluci´on de las estrellas muy masivas est´a dominada por su p´erdida de masa, aunque las tasas de p´erdida de masa no se conocen con mucha precisi´on, particularmente una vez que la estrella sale de la secuencia principal. Los estudios de las nebulosas de anillo y de las cascarones de HI que rodean a muchas estrellas Wolf-Rayet (WR) y variables azules luminosas (LBV) proporcionan algo de informaci´on acerca de la historia de la p´erdida de masa en las etapas previas. Durante la secuencia principal y la fase WR los vientos estelares hipers´onicos forman burbujas en el medio circunestelar e interestelar. Estas dos fases est´an separadas por una etapa en donde la estrella pierde masa a una tasa muy alta pero a baja velocidad. Por lo tanto, el ambiente presupernova es determinado por la estrella progenitora misma, aun´ hasta distancias de algunas decenas de parsecs de la estrella. En este art´ıculo, se describen las diferentes etapas en la evoluci´on del medio circunestelar alrededar de una estrella de masa 40 M mediante simulaciones num´ericas. ABSTRACT Mass loss dominates the evolution of very massive stars, although the mass loss rates are not known exactly, particularly once the star has left the main sequence. Studies of the ring nebulae and HI shells that surround many Wolf-Rayet (WR) and luminous blue variable (LBV) stars provide some information on the previous mass-loss history. -
EVOLUTION of the CRAB NEBULA in a LOW ENERGY SUPERNOVA Haifeng Yang and Roger A
Draft version August 23, 2018 Preprint typeset using LATEX style emulateapj v. 5/2/11 EVOLUTION OF THE CRAB NEBULA IN A LOW ENERGY SUPERNOVA Haifeng Yang and Roger A. Chevalier Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904; [email protected], [email protected] Draft version August 23, 2018 ABSTRACT The nature of the supernova leading to the Crab Nebula has long been controversial because of the low energy that is present in the observed nebula. One possibility is that there is significant energy in extended fast material around the Crab but searches for such material have not led to detections. An electron capture supernova model can plausibly account for the low energy and the observed abundances in the Crab. Here, we examine the evolution of the Crab pulsar wind nebula inside a freely expanding supernova and find that the observed properties are most consistent with a low energy event. Both the velocity and radius of the shell material, and the amount of gas swept up by the pulsar wind point to a low explosion energy ( 1050 ergs). We do not favor a model in which circumstellar interaction powers the supernova luminosity∼ near maximum light because the required mass would limit the freely expanding ejecta. Subject headings: ISM: individual objects (Crab Nebula) | supernovae: general | supernovae: indi- vidual (SN 1054) 1. INTRODUCTION energy of 1050 ergs (Chugai & Utrobin 2000). However, SN 1997D had a peak absolute magnitude of 14, con- The identification of the supernova type of SN 1054, − the event leading to the Crab Nebula, has been an en- siderably fainter than SN 1054 at maximum.