DOCSLIB.ORG

Through the Past, Brightly

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Through the Past, Brightly Through the Past, Credit: Edo Berger, Harvard University. Harvard University. Credit: Edo Berger, Brightly Gamma-Ray Bursts and the Early Universe By Sarah Harland-Logan Midnight Messages one GRB is equivalent to the energy ust like many undergraduates, Pro- output of 1,000 stars the size of the Jfessor Edo Berger (of the Harvard Sun, throughout their entire lives (3). astronomy department) is used to These incredibly intense bursts of receiving the occasional late-night gamma radiation (the highest-energy text message. Berger’s midnight texts, portion of the light spectrum) are now however, are sent to his iPhone directly believed to occur somewhere in the from NASA’s Swift telescope, our universe at least once to a few times per “The astronomy most powerful tool for detecting the day, and perhaps far more frequently phenomena known as Gamma-Ray (3, 6). Berger typically receives about equivalent of Bursts (GRBs) (1). Berger holds the two texts per week informing him of working at the ER” record for discovering the most dis- the appearance of a new one. At this tant, and therefore the oldest, object point, he will “Jump out of bed and in the known universe; this object is start calling observatories around the somewhat disappointingly named world to observe the burst,” and then GRB 090423 (to indicate that it was begin analyzing its properties as soon discovered on April 23, 2009) (2, 3). as possible (1). GRBs are the brightest objects in the Some of us might resent this frequent known universe, and the most power- incursion upon our sleep patterns, but ful explosions since the Big Bang (4, Berger explains that the unpredictable 5). For the brief period that a GRB is and “fast-paced nature” of his work is occurring, it shines thousands of times “part of the fun.” He describes his job more brightly than the entire galaxy in as “the astronomy equivalent of work- which it resides (1). In fact, GRBs are ing at the ER,” and is happy both to so bright that the energy released by be free from the type of work “where fall 2010 Harvard Science Review 9 GRBs went unnoticed until mid- ing it, and autonomously reorients itself 1969, when physicist Ray Klebasabel in the direction of the burst, where it was working with the data produced observes the burst’s afterglow. Perhaps by Vela, and noticed an earlier burst unsurprisingly, both types of GRBs are of gamma radiation that had to be now believed to result from the forma- extraterrestrial in origin (6, 7, 8). His tion of black holes, everyone’s favorite GLVFRYHU\FDWDO\]HGDÀHUFHGHEDWHRQ space monsters (4, 9). the origin and nature of GRBs that would continue for decades (1). Like Black Holes and Revelations any good scientific mystery, GRBs GRBs are subdivided into two cat- soon attracted a spectacular array of egories, “long” and “short.” Long theories, which ran the gamut from the GRBs, which can last for hundreds of reasonable-sounding (e.g., GRBs were seconds, begin life with the supernova caused by collisions between comets of a star at least 20 to 30 times (and Credit: Edo Berger (Harvard). and neutron stars) to the hilariously perhaps even 100 times) more massive outlandish (e.g., they were produced than the Sun (1). When giant stars like Figure 1. The record-breaking GRB (090423). not by Soviet nuclear testing but rather these explode, a black hole is created at by alien nuclear warfare) (6, 8). A 1975 the center of the supernova, and matter people . plan things months in ad- review paper presented at the Texas from the exploded star then forms an vance,” and that he and his colleagues Symposium on Relativistic Astrophys- accretion disc around the black hole. actually get “to look at pretty pictures ics included literally 100 different GRB As this taurus of material is sucked of the universe in real time” (also unlike theories (6). into the black hole, some of the mat- many astrophysicists) (1). 7RGD\WKHUHPDUNDEOH*5%ÀQGLQJ ter is ejected (along with electromag- satellite Swift (named for the bird) en- netic radiation), at velocities as high as Star Wars? ables scientists to make rapid progress 99.9995% of the speed of light (10); the +XPDQVÀUVWHQFRXQWHUHG*DPPD toward GRBs’ true origin. Swift has precise details of this process are still Ray Bursts by unknown to accident, dur- cosmolo- ing a military gists (11). o p e r a t i o n . The matter T h e f i r s t is thrown GRB detec- o u t w a r d tion occurred in several on July 2, d i f f e r e n t 1967, thanks “ s h e l l s , ” to a U.S. De- each travel- p a r t m e n t ing at a dif- of Defense ferent speed program that (3). GRBs launched the occur when Vela satellite more rap- system, in or- idly mov- der to moni- ing “shells” Credit: Lynn Cominski, Sonoma. Credit: Lynn tor Soviet catch up compliance to slower with the Nu- Figure 2. Accumulated GRB map, highlighting the most recent burst at any given moment (April 15, 2010). shells and clear Test Ban Credit: Lynn Cominski, Sonoma. c o l l i d e Treaty. The with them, 9HODVDWHOOLWHVZHUHÀWWHGZLWKHTXLS- LGHQWLÀHGDSSUR[LPDWHO\*5%VSHU releasing very high-energy photons; ment that could detect gamma-rays, so year since its launch on November 20th, hundreds of these collisions are pos- as to identify the radiation signature of 2004 (4). It alerts astrophysicists like sible in a single GRB (3, 11, 12). any Soviet warheads illegally detonated Dr. Berger to the location of each new But although astrophysicists are in space (6, 7, 8). GRB within about 1 minute of detect- FRQÀGHQWWKDWORQJ*5%VDUHLQGHHG 10 Harvard Science Review fall 2010 ORFDOL]HWKHPZLWKVXIÀFLHQWSUHFLVLRQ to identify their host galaxies, quantify how much energy they release, and GHÀQLWLYHO\DVVRFLDWHORQJ*5%VZLWK supernovae (15, 16, 17). Without the afterglows, we would still be groping around in the dark. Illuminating the Cosmic Dark Age Not only are GRBs interesting phe- nomena in themselves, but Dr. Berger and his colleagues hope to use them as ´WKHEHVWÁDVKOLJKWµWRLOOXPLQDWHWKH early history of the universe (1). Dr. Berger reminded me that “When we look at the universe, we’re looking at light travelling from distant objects. Figure 3. GRB 090423 shatters distance records. Brilliant Afterglows *LYHQWKDWWKHVSHHGRI OLJKWLVÀQLWHµ We owe the preponderance of our the more distant the object we are produced from these supernovae, current GRB knowledge to the 1997 looking at, “the further back in time Berger emphasized that their origin detection (by the BeppoSAX satellite) we’re looking.” In other words, “the story is not yet complete, because “we of the “afterglows” that they leave key” to answering questions like “How only have one GRB for every 1,000 behind; we are currently able to detect GLGWKHÀUVWVWDUVIRUP"µLVWR´ORRNDW supernova explosions. We must need about two-thirds of them (15, 16, 17). extremely distant objects, [from] when something very special to happen [to Once the collisions of the ejected shells the universe was young” (1). produce a GRB]; we just don’t know of matter have ceased (and therefore Between the beginning of time and what it is. Yet.” (1) the GRB is over), the large shell that has the present day, the universe passed The story of short GRBs, which resulted from these collisions continues through a period of literal darkness can be as brief as a few milliseconds, to travel outward at nearly the speed of that is referred to as the Cosmic Dark remains enmeshed in even greater mys- light, colliding with the interstellar me- Age. In the aftermath of the Big Bang, tery. The current theory (which Berger dium; Dr. Berger compares its advance the universe was incredibly hot, and its emphasizes is “something that we’re to “a snowplow pushing snow.” (18) matter was entirely ionized (1, 9); the [still] trying to prove or disprove at this formation of atoms did not occur for point”) is that they are produced when about 400,000 years (1). This process a pair of neutron stars nearly collide, Dr. Berger’s record-holding GRB has a redshift of 8.2, which created the Cosmic Microwave Back- after the stars lose the angular momen- ground (CMB), the low-level micro- tum that keeps their orbit stable (1, 6). means that this GRB occurred wave radiation that glows evenly at As Berger colorfully puts it, “eventually about 630 million years after all points throughout the cosmos (5). they get so close to each other that the Big Bang; the light from During this period, the universe they’re almost touching; then they start was plunged into darkness, since vis- shredding each other. At the end, this burst has been traveling for over 13 of the universe’s ible light was absorbed by clouds of they don’t actually collide; but they hydrogen gas. Since ionized matter just tear each other apart, in those last 13.7 billion years of existence. DOORZVSKRWRQVWRÁRZIUHHO\ZKHUHDV few seconds.” (1) A black hole forms atomic gas absorbs them (18), the uni- at the site of the shredded remnant; it This collision generates emissions in the YHUVHUHPDLQHGGDUNXQWLOWKHÀUVWVWDUV is surrounded by an accretion disc of lower portions of the spectrum (X-rays, had been formed. Photons emitted by matter from the neutron stars, which is optical, and microwaves), which linger the early stars and galaxies then “re- sucked into the black hole; and again, for a period ranging from days to years ionized” the matter of the intergalactic this process drives the incredibly rapid (1, 12).
Load more

Recommended publications
  • Joint Astrophysics Nascent Universe Satellite:. Utilizing Grbs As High Redshift Probes
    University of New Hampshire University of New Hampshire Scholars' Repository Physics Scholarship Physics 2012 Joint Astrophysics Nascent Universe Satellite:. utilizing GRBs as high redshift probes P. W. A. Roming Southwest Research Institute S. G. Bilen Pennsylvania State University - Main Campus D. N. Burrows Pennsylvania State University - Main Campus A Falcone University of New Hampshire - Main Campus D. B. Fox Pennsylvania State University - Main Campus See next page for additional authors Follow this and additional works at: https://scholars.unh.edu/physics_facpub Part of the Astrophysics and Astronomy Commons Recommended Citation Roming, P. W. A., S. G. Bilen, D. N. Burrows, A. D. Falcone, D. B. Fox, T. L. Herter, J. A. Kennea, M. L. McConnell, J. A. Nousek. JOINT ASTROPHYSICS NASCENT UNIVERSE SATELLITE:. UTILIZING GRBS AS HIGH REDSHIFT PROBES. 2012, Memorie della Societa Astronomica Italiana Supplement, 21, pp.155-161. This Article is brought to you for free and open access by the Physics at University of New Hampshire Scholars' Repository. It has been accepted for inclusion in Physics Scholarship by an authorized administrator of University of New Hampshire Scholars' Repository. For more information, please contact [email protected]. Authors P. W. A. Roming, S. G. Bilen, D. N. Burrows, A Falcone, D. B. Fox, T. L. Herter, J. A. Kennea, Mark L. McConnell, and J. A. Nousek This article is available at University of New Hampshire Scholars' Repository: https://scholars.unh.edu/ physics_facpub/348 Mem. S.A.It. Suppl. Vol. 21, 155 Memorie della c SAIt 2012 Supplementi Joint Astrophysics Nascent Universe Satellite: utilizing GRBs as high redshift probes P.
    [Show full text]
  • Exploring Dust Extinction at the Edge of Reionization
    Draft version October 15, 2018 Preprint typeset using LATEX style emulateapj v. 11/10/09 EXPLORING DUST EXTINCTION AT THE EDGE OF REIONIZATION Tayyaba Zafar,1 Darach J. Watson,1 Nial R. Tanvir,2 Johan P. U. Fynbo,1 Rhaana L.C.Starling,2 and Andrew J. Levan3 Draft version October 15, 2018 ABSTRACT The brightness of gamma-ray burst (GRB) afterglows and their occurrence in young, blue galaxies make them excellent probes to study star forming regions in the distant Universe. We here elucidate dust extinction properties in the early Universe through the analysis of the afterglows of all known z > 6 GRBs: GRB090423, 080913 and 050904, at z = 8.2, 6.69, and 6.295, respectively. We gather all available optical and near-infrared photometry, spectroscopy and X-ray data to construct spectral energy distributions (SEDs) at multiple epochs. We then fit the SEDs at all epochs with a dust-attenuated power-law or broken power-law. We find no evidence for dust extinction in GRB050904 and GRB090423, with possible evidence for a low level of extinction in GRB080913. We compare the high redshift GRBs to a sample of lower redshift GRB extinctions and find a lack of even moderately extinguished events (AV ∼ 0.3) above z & 4. In spite of the biased selection and small number statistics, this result hints at a decrease in dust content in star-forming environments at high redshifts. Subject headings: dark ages, reionization, first stars – dust, extinction – galaxies: high-redshift – gamma-ray burst: individual (GRB090423, 080913, and 050904) 1. INTRODUCTION ing made in the rest frame UV, they are in principle relatively Dust formationin the early universeis a hotly debated topic.
    [Show full text]
  • Signals from the Beginnings of the World
    Fundamental forces in space: For a few seconds, a gamma-ray burst radiates as brightly as the whole universe together, the radiation emanating to the outside via two jets. Events such as these still hide their secret: is it the explosion of an extremely massive star, a neutron star falling into the gravitational maelstrom of a black hole, or the fusion of two neutron stars or black holes? xxx 46 MaxPlanckResearch 3 | 09 PHYSICS & ASTRONOMY_Gamma-Ray Bursts Signals from the Beginning of the World A star exploded just 625 million years after the Big Bang, but the radiation of this event didn’t reach Earth until last spring. This gamma-ray burst was named GRB 090423. It is the most distant astronomical object yet discovered. Jochen Greiner and his colleagues at the Max Planck Institute for Extraterrestrial Physics in Garching investigate such cosmic ‘ignition sparks’ at the edge of space and time. TEXT HELMUT HORNUNG t must have been a violent catastro- In the years that followed, scientists into radiation with incredibly high ef- phe. Somewhere in the early uni- investigated the gamma-ray burst phe- ficiency. Over the years, astrophysicists verse, a star blew up – a heavyweight nomenon with instruments designed have put forward at least 150 different with several times the mass of our specifically for this purpose. theories – most of which have since Sun. In the course of this detona- From 1991 until its controlled crash been dismissed. Ition, within less than ten seconds, nine years later, the Compton space The issue is further complicated by as much energy was released as the observatory registered about 2,000 two sub-classes that were discovered Sun has produced during its entire gamma-ray flashes (MAXPLANCKRESEARCH through Compton measurements: gam- 10-billion-year lifetime.
    [Show full text]
  • ALMA Observations of the Host Galaxy of GRB 090423 at Z= 8.23
    DRAFT VERSION AUGUST 13, 2014 Preprint typeset using LATEX style emulateapj v. 03/07/07 ALMA OBSERVATIONS OF THE HOST GALAXY OF GRB 090423 AT z =8.23: DEEP LIMITS ON OBSCURED STAR FORMATION 630 MILLION YEARS AFTER THE BIG BANG E. BERGER1,B.A.ZAUDERER1, R.-R. CHARY1,2 , T. LASKAR1,R.CHORNOCK1,N.R.TANVIR3,E.R.STANWAY4,A.J.LEVAN4, E.M. LEVESQUE5,&J.E.DAVIES1 Draft version August 13, 2014 ABSTRACT We present rest-frame far-infrared (FIR) and optical observations of the host galaxy of GRB090423 at z = 8.23 from the Atacama Large Millimeter Array (ALMA) and the Spitzer Space Telescope, respectively. The host remains undetected to 3σ limits of Fν(222GHz) . 33 µJy and Fν (3.6µm) . 81 nJy. The FIR limit is about 20 times fainter than the luminosity of the local ULIRG Arp220, and comparable to the local starburst M82. Comparing to model spectral energy distributions we place a limit on the IR luminosity of LIR(8 − 1000µm) . 10 −1 3×10 L⊙, correspondingto a limit on the obscuredstar formationrate of SFRIR . 5M⊙ yr ; for comparison, the limit on the unobscured star formation rate from Hubble Space Telescope rest-frame UV observations is −1 7 SFRUV . 1M⊙ yr . We also place a limit on the host galaxy stellar mass of M∗ . 5 × 10 M⊙ (for a stellar population age of 100 Myr and constant star formation rate). Finally, we compare our millimeter observations to those of field galaxies at z & 4 (Lyman break galaxies, Lyα emitters, and submillimeter galaxies), and find that our limit on the FIR luminosity is the most constraining to date, although the field galaxies have much larger rest-frame UV/optical luminosities than the host of GRB090423 by virtue of their selection techniques.
    [Show full text]
  • Observed Cosmological Redshifts Support Contracting Accelerating Universe
    Observed Cosmological Redshifts Support Contracting Accelerating Universe Branislav Vlahovic∗ Department of Physics, North Carolina Central University, 1801 Fayetteville Street, Durham, NC 27707 USA. The main argument that Universe is currently expanding is observed redshift increase by distance. However, this conclusion may not be correct, because cosmological redshift depends only on the scaling factors, the change in the size of the universe during the time of light propagation and is not related to the speed of observer or speed of the object emitting the light. An observer in expanding universe will measure the same redshift as observer in contracting universe with the same scaling. This was not taken into account in analysing the SN Ia data related to the universe acceleration. Possibility that universe may contract, but that the observed light is cosmologically redshifted allows for completely different set of cosmological parameters ΩM ; ΩΛ, including the solution ΩM = 1; ΩΛ = 0. The contracting and in the same time accelerating universe explains observed deceleration and acceleration in SN Ia data, but also gives significantly larger value for the age of the universe, t0 = 24 Gyr. This allows to reconsider classical cosmological models with Λ = 0. The contracting stage also may explain the observed association of high redshifted quasars to low redshifted galaxies. COSMOLOGICAL REDSHIFT period t0 − te. Cosmological redshift is not related to the speed of the In co-moving Robertson-Walker coordinate system, re- object that emits the light nor the speed of observer. It is lation between the redshift z, in the frequencies of spec- also not related to the relative velocity between objects.
    [Show full text]
  • Scrambling to Read the Meaning of the Sky's Most Ancient Flare
    NEWSFOCUS ASTRONOMY Tanvir, starting the observation some 21 minutes after the burst. “We observed the target for 20 minutes, and then the wind got Scrambling to Read the Meaning too much for us,” he says. Thousands of kilometers away, sitting in an Of the Sky’s Most Ancient Flare auditorium listening to talks about the future of U.K. astronomy, Tanvir kept glancing at his This spring, a seemingly routine gamma ray burst triggered a worldwide race to catch laptop in anticipation of the first images. He a glimpse of the early universe was also in touch with scientists operating Gemini Observatory’s 8-meter North tele- On 23 April, astrophysicist Nial Tanvir had networks make possible worldwide, round- scope, also on Mauna Kea, which had begun just dropped his daughter off at school when the-clock collaborations, and pressures for taking observations in the optical band within an automated text message appeared on his cooperation and competition often come into minutes of the burst. cell phone. NASA’s Swift satellite had just simultaneous play. “This is extreme astron- The burst appeared as a fuzzy spot in near- detected a gamma ray burst (GRB)—a brief omy,” says Don Lamb, a theoretical astrophysi- infrared images taken by UKIRT but didn’t flash of high-energy radiation emitted by a cist at the University of Chicago in Illinois. show up in optical images taken by Gemini. To star collapsing to form a black hole. “Oh boy, Tanvir and others, this was a clue that it had here we go again,” Tanvir, a researcher at the All-night dash occurred at a high redshift: Visible light from University of Leicester in the United King- Shortly after Tanvir received the alert, he was the burst had shifted to the near-infrared, and dom, recalls thinking.
    [Show full text]
  • GRB 090423 at a Redshift of Z ≈
    Vol 461 | 29 October 2009 | doi:10.1038/nature08445 LETTERS GRB 090423 at a redshift of z < 8.1 R. Salvaterra1, M. Della Valle2,3,4, S. Campana1, G. Chincarini1,5, S. Covino1, P. D’Avanzo1,5, A. Ferna´ndez-Soto6, C. Guidorzi7, F. Mannucci8, R. Margutti1,5,C.C.Tho¨ne1, L. A. Antonelli9, S. D. Barthelmy10, M. De Pasquale11, V. D’Elia9, F. Fiore9, D. Fugazza1, L. K. Hunt8, E. Maiorano12, S. Marinoni13,14, F. E. Marshall10, E. Molinari1,13, J. Nousek15, E. Pian16,17, J. L. Racusin15, L. Stella9, L. Amati12, G. Andreuzzi13, G. Cusumano18, E. E. Fenimore19, P. Ferrero20, P. Giommi21, D. Guetta9, S. T. Holland10,22,23, K. Hurley24, G. L. Israel9, J. Mao1, C. B. Markwardt10,23,25, N. Masetti12, C. Pagani15, E. Palazzi12, D. M. Palmer18, S. Piranomonte9, G. Tagliaferri1 & V. Testa9 Gamma-ray bursts (GRBs) are produced by rare types of massive The spectrum (Fig. 2) reveals a clear break at a wavelength of stellar explosion. Their rapidly fading afterglows are often bright 1.1 mm (ref. 8). We derive a spectroscopic redshift for the GRB of z0:1 enough at optical wavelengths that they are detectable at cos- z 5 8:1{0:3 (ref. 9; see Supplementary Information, section 3), inter- mological distances. Hitherto, the highest known redshift for a preting the break as Lyman-a absorption in the intergalactic med- GRB was z 5 6.7 (ref. 1), for GRB 080913, and for a galaxy was ium. No other significant absorption features were detected. This z 5 6.96 (ref.
    [Show full text]
  • Evidence for Low Extinction in Actively Star Forming Galaxies at Z $> $6.5
    Accepted for publication in the Astrophyscial Journal A Preprint typeset using LTEX style emulateapj v. 5/2/11 EVIDENCE FOR LOW EXTINCTION IN ACTIVELY STAR FORMING GALAXIES AT Z>6.5. F. Walter 1, R. Decarli 1, C. Carilli 2, D. Riechers 3, F. Bertoldi 4, A. Weiß 5, P. Cox 6, R. Neri 6, R. Maiolino 7, M. Ouchi 8, E. Egami 9, K. Nakanishi 10,11,12 Draft version July 18, 2018 ABSTRACT We present a search for the [C II] 158µm fine structure line (a main cooling line of the interstel- lar medium) and the underlying far–infrared (FIR) continuum in three high–redshift (6.6<z<8.2) star–forming galaxies using the IRAM Plateau de Bure interferometer. We targeted two Lyman– α–selected galaxies (Lyman–Alpha–Emitters, LAEs) with moderate UV–based star formation rates −1 (SFR∼20 M⊙ yr ; Himiko at z=6.6 and IOK–1 at z=7.0) and a Gamma Ray Burst (GRB) host galaxy (GRB 090423 at z∼8.2). Based on our 3σ rest–frame FIR continuum limits, previous (rest– frame) UV continuum measurements and spectral energy distribution (SED) fitting, we rule out SED shapes similar to highly obscured galaxies (e.g. Arp 220, M 82) and less extreme dust–rich nearby spiral galaxies (e.g. M 51) for the LAEs. Conservatively assuming a SED shape typical of local spi- −1 ral galaxies we derive upper limits for the FIR–based star formation rates (SFRs) of ∼70 M⊙ yr , −1 −1 ∼50 M⊙ yr and ∼40 M⊙ yr for Himiko, IOK–1 and GRB 090423, respectively.
    [Show full text]
  • Effects of Rotation Arund the Axis on the Stars, Galaxy and Rotation of Universe* Weitter Duckss1
    Effects of Rotation Arund the Axis on the Stars, Galaxy and Rotation of Universe* Weitter Duckss1 1Independent Researcher, Zadar, Croatia *Project: https://www.svemir-ipaksevrti.com/Universe-and-rotation.html; (https://www.svemir-ipaksevrti.com/) Abstract: The article analyzes the blueshift of the objects, through realized measurements of galaxies, mergers and collisions of galaxies and clusters of galaxies and measurements of different galactic speeds, where the closer galaxies move faster than the significantly more distant ones. The clusters of galaxies are analyzed through their non-zero value rotations and gravitational connection of objects inside a cluster, supercluster or a group of galaxies. The constant growth of objects and systems is visible through the constant influx of space material to Earth and other objects inside our system, through percussive craters, scattered around the system, collisions and mergers of objects, galaxies and clusters of galaxies. Atom and its formation, joining into pairs, growth and disintegration are analyzed through atoms of the same values of structure, different aggregate states and contiguous atoms of different aggregate states. The disintegration of complex atoms is followed with the temperature increase above the boiling point of atoms and compounds. The effects of rotation around an axis are analyzed from the small objects through stars, galaxies, superclusters and to the rotation of Universe. The objects' speeds of rotation and their effects are analyzed through the formation and appearance of a system (the formation of orbits, the asteroid belt, gas disk, the appearance of galaxies), its influence on temperature, surface gravity, the force of a magnetic field, the size of a radius.
    [Show full text]
  • ALMA Observations of the Host Galaxy of GRB 090423 at Z = 8.23: Deep Limits on Obscured Star Formation 630 Million Years After the Big Bang
    ALMA Observations of the Host Galaxy of GRB 090423 at Z = 8.23: Deep Limits on Obscured Star formation 630 Million Years after the Big Bang. The Harvard community has made this article openly available. Please share how this access benefits you. Your story matters Citation Berger, E., B. A. Zauderer, R.-R. Chary, T. Laskar, R. Chornock, N. R. Tanvir, E. R. Stanway, A. J. Levan, E. M. Levesque, and J. E. Davies. 2014. "ALMA Observations of the Host Galaxy of GRB 090423 at Z = 8.23: Deep Limits on Obscured Star formation 630 Million Years after the Big Bang. ” The Astrophysical Journal 796 (2) (November 12): 96. doi:10.1088/0004-637x/796/2/96. Published Version doi:10.1088/0004-637x/796/2/96 Citable link http://nrs.harvard.edu/urn-3:HUL.InstRepos:30498353 Terms of Use This article was downloaded from Harvard University’s DASH repository, and is made available under the terms and conditions applicable to Open Access Policy Articles, as set forth at http:// nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of- use#OAP DRAFT VERSION AUGUST 13, 2014 Preprint typeset using LATEX style emulateapj v. 03/07/07 ALMA OBSERVATIONS OF THE HOST GALAXY OF GRB 090423 AT z =8.23: DEEP LIMITS ON OBSCURED STAR FORMATION 630 MILLION YEARS AFTER THE BIG BANG E. BERGER1,B.A.ZAUDERER1, R.-R. CHARY1,2 , T. LASKAR1,R.CHORNOCK1,N.R.TANVIR3,E.R.STANWAY4,A.J.LEVAN4, E.M. LEVESQUE5,&J.E.DAVIES1 Draft version August 13, 2014 ABSTRACT We present rest-frame far-infrared (FIR) and optical observations of the host galaxy of GRB090423 at z = 8.23 from the Atacama Large Millimeter Array (ALMA) and the Spitzer Space Telescope, respectively.
    [Show full text]
  • The Oldest Object
    RIGHT NOW DYING LIGHT The Oldest Object hen specialized sat- “within a few hundred million years.” ellites orbiting Earth Further research using gamma-ray bursts detect a star explod- may eventually pinpoint the moment ing anywhere in the when stars began to form. Wuniverse, Edo Berger gets an alert on his Cosmic explosions emit jets of gamma cell phone. At 3:55 a.m. on April 23, the rays, a more energetic form of light even assistant professor of astronomy learned than x-rays (see the artist’s conception, of a gamma-ray burst (GRB) from a star below). But gamma rays don’t tell any- almost as old as time itself. GRB 090423, thing about the distance to an object, so which exploded more than 13 billion years when Berger first learned of the gamma- ago, at a time when the universe was just ray burst, he asked the Gemini Observa- 625 million years old, is the oldest object tory in Hilo, Hawaii, to train its telescope Tomorrow’s healthcare yet discovered. The find was significant, on the dying star. leaders will need a broad he says, because it proved that stars began The fact that there was plenty of infra- forming very quickly after the big bang: red light, but no visible light, coming from perspective and solid the explosion was “a smoking gun”: he NSF management skills. knew at once that he had found an ancient star. That’s because the early BSERVATORY/ O universe was filled with hydrogen gas Yale MBA for Executives: EMINI opaque to visible light.
    [Show full text]
  • ASTROPHYSICS: Most Distant Cosmic Blast Seen
    ASTROPHYSICS: Most distant cosmic blast seen Bing Zhang The most distant γ-ray burst yet sighted is the earliest astronomical object ever observed in cosmic history. This ancient beacon offers a glimpse of the little-known cosmic dark ages. In this issue, two papers1,2 report the discovery a γ-ray burst (GRB) at a redshift of about 8.2. It is the highest redshift — or equivalently the most distant — astronomical object ever detected in the Universe. For comparison, the highest redshift recorded so far for galaxies is about 6.96 (ref. 3). For quasars — extremely bright galactic nuclei powered by supermassive black holes — the record holder is an object at 6.48 (ref. 4). Tanvir et al.1 (page 1254) and Salvaterra et al.2 (page 1258) measured a concordant redshift for GRB 090423 on the basis of observations of its fading afterglow emission at different times after the initial burst of γ-rays. In astronomy, a larger distance (or redshift) corresponds to an earlier time in cosmic history, because it takes longer for a farther- away photon, which travels at finite speed, to reach Earth. Moreover, because the Universe is expanding, the wavelength of electromagnetic radiation emitted by a distant object is stretched to be longer and redder (redshifted) on its course to Earth. The farther away the source, the more the Universe has expanded, and therefore the higher the source’s redshift. The redshift measured for GRB 090423 means that the burst occurred at a time when the Universe was about nine times smaller than it is today — putting the timing of the event at about 630 million years after the Big Bang.
    [Show full text]