SN 2014J

Coordinates: Sky map 9h 55m 42.217s, +69° 40′ 26.56″

SN 2014J
SN 2014J University of London Observation
First image: Messier 82 on 10 December 2013. Second image: The same view on 22 January 2014. The position of the supernova is marked.
Right ascension 9h 55m 42.217s[1]
Declination69° 40′ 26.56″[1]
EpochJ2000
Distance11,500,000 ly (3,500,000 pc)
HostMessier 82
Progenitorunknown
Notable featuresClosest Type Ia for 40 years

SN 2014J was a type-Ia supernova in Messier 82 (the 'Cigar Galaxy', M82) discovered in mid-January 2014.[2] It was the closest type-Ia supernova discovered for 42 years, and none have been closer as of 2018. The supernova was discovered by chance during an undergraduate teaching session at the University of London Observatory. It peaked on 31 January 2014, reaching an apparent magnitude of 10.5.[3] SN 2014J was the subject of an intense observing campaign by professional astronomers and was bright enough to be seen by amateur astronomers.

Discovery

Mill hill observatory 2009
University of London Observatory, where SN 2014J was discovered.

The supernova was discovered by astronomer Steve Fossey, of University College London. Fossey was training four undergraduate students (Ben Cooke, Guy Pollack, Matthew Wilde and Thomas Wright) to use a small 0.35-metre (14 in) telescope at University of London Observatory, located in Mill Hill, north London.[4][5][6]

The discovery was serendipitous, because Fossey was not searching for supernovae, had not planned to look at M82, and only wanted to take advantage of a short gap in the London cloud cover. He later said that "The weather was closing in, with increasing cloud, so instead of the planned practical astronomy class, I gave the students an introductory demonstration of how to use the CCD camera on one of the observatory’s automated 0.35–metre telescopes."[5]

At 19:20 GMT on 21 January 2014, Fossey and his students noticed a bright new star in their images of the galaxy Messier 82, also known as the Cigar Galaxy.[5] After comparing their image to archival ones of the same galaxy, they used observations with a second telescope to eliminate the possibility of an instrumental artefact.[6] Their discovery was reported to the International Astronomical Union's Central Bureau for Astronomical Telegrams, who confirmed that they were the first to spot the supernova and assigned it the name SN 2014J as the tenth supernova discovered in 2014.[5]

Observations

Opo1742a
Light echo around SN 2014J in M82.[7]

Follow-up adaptive optics observations with the 10-metre (390 in) Keck telescope at Mauna Kea Observatory, Hawaii were used to precisely determine the location of the new supernova.[1] The first optical spectrum was obtained using the 3.5-metre (140 in) ARC telescope in New Mexico, which showed the supernova to be of Type Ia.[8] Pre-discovery recovery images were found that showed the supernova as early as 15 January, six days before discovery.[9]

Early indications were that the supernova had been discovered approximately 14 days before maximum light, so it would get brighter over the following fortnight.[8] It was predicted to be bright enough to be visible with binoculars throughout the Northern Hemisphere.[4] The supernova continued to get brighter until 31 January, when it peaked at an apparent magnitude of 10.5.[3]

SN 2014J was a popular target for amateur astronomers because it was located close to The Plough asterism (the 'Big Dipper') and visible all night for most Northern Hemisphere observers.[10][11]

Its unusual brightness and relative closeness led to SN 2014J becoming the subject of intense follow-up observations by astronomers worldwide,[6] including with the Hubble Space Telescope.[12] Over a hundred scientific papers have discussed the supernova.[13][14]

Physical properties

The relative closeness of the supernova allowed astronomers to study it in much more detail than usual. Type Ia supernovae are especially important as standard candles in physical cosmology, and astronomers hope that SN 2014J will help them understand how these supernovae form and evolve.[6]

SN2014J was observed by the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) which detected the gamma-ray spectral lines characteristic of the radioactive decay chain 56Ni→56Co→56Fe.[15] This was the first time these lines were detected in a Type Ia supernova, providing support for the standard model that this class of supernova produces large quantities of 56Ni through nucleosynthesis.[16]

Observations of the diffuse interstellar bands in the spectrum of the supernova indicated that it lay behind a significant quantity of interstellar medium in M82. The supernova therefore suffered from interstellar extinction, with a reddening of at least one magnitude.[17] The degree of light extinction from M82 dust blocking SN 2014J reduces its value as an observational prototype for Type Ia supernovae, but makes it a powerful probe of the interstellar medium of M82.[18]

Researchers used archival images from the Hubble Space Telescope to study the environment of SN 2014J prior to the supernova, hoping to identify the progenitor system,[19] but found no identifiable progenitor star.[20] This is not unexpected, because the progenitors of type Ia supernovae are thought to be white dwarfs in binary systems,[21] and observation of SN 2014J provided empirical confirmation for this.[22] The white dwarf is much too faint to detect at the distance of M82, but its companion would have been detectable if it had been a bright evolved giant star. It will however remain too faint if it is a second white dwarf (the double degenerate Type Ia supernova path), a lower main-sequence star, or even a giant star on the fainter part of the giant sequence.

Distance

At a distance of 11.5 ± 0.8 million light-years (3.5 ± 0.3 megaparsecs),[23] SN 2014J was one of the closest supernovae seen for decades. It was the closest type Ia supernova since SN 1972E,[10] and the closest supernova of any type since 2004. Some sources initially stated that SN 2014J was the closest supernova of any type since SN 1987A,[4] but this claim is erroneous.[10] The last supernova that was unambiguously closer to Earth than SN 2014J was SN 2004dj, a type II-P supernova in the galaxy NGC 2403, 8 million light-years from Earth. SN 1993J was a type IIb supernova at almost the same distance as SN 2014J, because it was located in Messier 81, which together with Messier 82 and NGC 3077 forms the core of the M81 group of galaxies.[5]

See also

References

  1. ^ a b c Tendulkar, S. P.; Liu, M. C.; Dupuy, T. J.; Ca, Y. (23 January 2014). "Near-IR Adaptive Optics Localization of PSN J09554214+6940260". The Astronomer's Telegram. 5789: 5789. Bibcode:2014ATel.5789....1T. Retrieved 23 January 2014.
  2. ^ "Supernova SN 2014J". Observation Logbook. Carleton University. 22 January 2014. Archived from the original on 1 February 2014. Retrieved 27 January 2014. This is the closest type Ia supernova observed in the last 40 years.
  3. ^ a b Alan MacRobert (17 February 2014). "Supernova in M82 Passes Its Peak - Sky & Telescope". Skyandtelescope.com. Retrieved 22 December 2016.
  4. ^ a b c "Nearby supernova dazzles astronomers". BBC News. 23 January 2014. Retrieved 23 January 2014. the closest supernova to Earth that has been seen in decades
  5. ^ a b c d e "Supernova in Messier 82 discovered by UCL students" (Press release). University College London. 22 January 2014. Retrieved 23 January 2014.
  6. ^ a b c d Lucas, Laursen (22 January 2014). "Supernova erupts in nearby galaxy". Nature News. doi:10.1038/nature.2014.14579. Retrieved 23 January 2014.
  7. ^ "Light Echo around SN 2014J in M82". www.spacetelescope.org. Retrieved 15 November 2017.
  8. ^ a b Cao, Y.; Kasliwal, M. M.; McKay, A.; Bradley, A. (22 January 2014). "Classification of Supernova in M82 as a young, reddened Type Ia Supernova". The Astronomer's Telegram. 5786: 5786. Bibcode:2014ATel.5786....1C. Retrieved 23 January 2014.
  9. ^ Ma, Bin; Wei, Peng; Shang, Zhaohui; Wang, Lifan; Wang, Xiaofeng (23 January 2014). "Prediscovery Observations of SN 2014J in M82 from the Antarctic Survey Telescope". The Astronomer's Telegram. 5794: 5789. Bibcode:2014ATel.5794....1M. Retrieved 23 January 2014.
  10. ^ a b c MacRobert, Alan (22 January 2014). "Bright Supernova in M82". Sky & Telescope. Retrieved 27 January 2014. this is said to be the nearest supernova since 1972 of Type Ia
  11. ^ King, Bob (22 January 2014). "Bright New Supernova Blows Up in Nearby M82, the Cigar Galaxy". Universe Today. Retrieved 23 January 2014.
  12. ^ Foley, Ryan (24 January 2014). "HST Observations of SN 2014J". The Astronomer's Telegram. 5811: 5789. Bibcode:2014ATel.5811....1F. Retrieved 25 January 2014.
  13. ^ "ADS results for SN 2014J". NASA Astrophysics Data System. Retrieved 9 May 2016.
  14. ^ "SN 2014J bibliography". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 9 May 2016.
  15. ^ Churazov, E.; Sunyaev, R.; Grebenev, S.; Isern, J.; Jean, P.; Knodlseder, J.; Lebrun, F.; Renaud, M.; Bravo, E.; Diehl, R.; Kuulkers, E. (20 March 2014). "Detection of the 847 keV gamma-ray line of radio-active Co56 from the Type Ia Supernova SN2014J in M82 with INTEGRAL". The Astronomer's Telegram. 5992: 5992. Bibcode:2014ATel.5992....1C. Retrieved 20 March 2014.
  16. ^ Churazov, E.; Sunyaev, R.; Isern, J.; Knödlseder, J.; Jean, P.; Lebrun, F.; Chugai, N.; Grebenev, S.; Bravo, E. (2014). "Cobalt-56 γ-ray emission lines from the type Ia supernova 2014J". Nature. 512 (7515): 406–408. arXiv:1405.3332. Bibcode:2014Natur.512..406C. doi:10.1038/nature13672.
  17. ^ Cox, Nick; Davis, P.; Patat, F.; Van Winckel, Hans (23 January 2014). "High-resolution spectroscopy of SN2014J in M82". The Astronomer's Telegram. 5797: 5789. Bibcode:2014ATel.5797....1C. Retrieved 25 January 2014.
  18. ^ Ritchey, Adam M.; Welty, Daniel E.; Dahlstrom, Julie A.; York, Donald G. (2015). "Diffuse Atomic and Molecular Gas in the Interstellar Medium of M82 toward SN 2014J". The Astrophysical Journal. 799 (2): 197. arXiv:1407.5723. Bibcode:2015ApJ...799..197R. doi:10.1088/0004-637X/799/2/197.
  19. ^ Goobar, A; Johansson, J; Amanullah, R; Cao, Y; Perley, D. A; Kasliwal, M. M; Ferretti, R; Nugent, P. E; Harris, C; Gal-Yam, A; Ofek, E. O; Tendulkar, S. P; Dennefeld, M; Valenti, S; Arcavi, I; Banerjee, D. P. K; Venkataraman, V; Joshi, V; Ashok, N. M; Cenko, S. B; Diaz, R. F; Fremling, C; Horesh, A; Howell, D. A; Kulkarni, S. R; Papadogiannakis, S; Petrushevska, T; Sand, D; Sollerman, J; et al. (2014). "The Rise of Sn 2014J in the Nearby Galaxy M82". The Astrophysical Journal. 784: L12. arXiv:1402.0849. Bibcode:2014ApJ...784L..12G. doi:10.1088/2041-8205/784/1/L12.
  20. ^ Kelly, Patrick L.; Fox, Ori D.; Filippenko, Alexei V.; Cenko, S. Bradley; et al. (2014). "Constraints on the Progenitor System of the Type Ia Supernova 2014J from Pre-Explosion Hubble Space Telescope Imaging". The Astrophysical Journal. 790: 3. arXiv:1403.4250. Bibcode:2014ApJ...790....3K. doi:10.1088/0004-637X/790/1/3.
  21. ^ Mazzali; Röpke; Benetti; Hillebrandt (2007). "A Common Explosion Mechanism for Type Ia Supernovae". Science. 315 (5813): 825–828. arXiv:astro-ph/0702351. Bibcode:2007Sci...315..825M. doi:10.1126/science.1136259. PMID 17289993.
  22. ^ Drake, Nadia (28 August 2014). "Type 1a Supernovae: Why Our Standard Candle Isn't Really Standard". National Geographic.
  23. ^ Karachentsev, I. D.; Kashibadze, O. G. (2006). "Masses of the local group and of the M81 group estimated from distortions in the local velocity field". Astrophysics. 49 (1): 3–18. Bibcode:2006Ap.....49....3K. doi:10.1007/s10511-006-0002-6.

External links

History of supernova observation

The known history of supernova observation goes back to 185 AD, when supernova SN 185 appeared, the oldest appearance of a supernova recorded by humankind. Several additional supernovae within the Milky Way galaxy have been recorded since that time, with SN 1604 being the most recent supernova to be observed in this galaxy.Since the development of the telescope, the field of supernova discovery has expanded to other galaxies. These occurrences provide important information on the distances of galaxies. Successful models of supernova behavior have also been developed, and the role of supernovae in the star formation process is now increasingly understood.

Light echo

A light echo is a physical phenomenon caused by light reflected off surfaces distant from the source, and arriving at the observer with a delay relative to this distance. The phenomenon is analogous to an echo of sound, but due to the much faster speed of light, it mostly only manifests itself over astronomical distances.

For example, a light echo is produced when a sudden flash from a nova is reflected off a cosmic dust cloud, and arrives at the viewer after a longer duration than it otherwise would have taken with a direct path. Because of their geometries, light echoes can produce the illusion of superluminal motion.

List of supernovae

This is a list of supernovae that are of historical significance. These include supernovae that were observed prior to the availability of photography, and individual events that have been the subject of a scientific paper that contributed to supernova theory.

M82 X-2

M82 X-2 is an X-ray pulsar located in the galaxy Messier 82, approximately 12 million light-years from Earth. It is exceptionally luminous, radiating energy equivalent to approximately ten million Suns. This object is part of a binary system: If the pulsar is of an average size, 1.4 M☉, then its companion is at least 5.2 M☉. On average, the pulsar rotates every 1.37 seconds, and revolves around its more massive companion every 2.5 days.M82 X-2 is an ultraluminous X-ray source (ULX), shining about 100 times brighter than theory suggests something of its mass should be able to. Its brightness is many times higher than the Eddington limit, a basic physics guideline that sets an upper limit on the brightness that an object of a given mass should be able to achieve. Possible explanations for violations of the Eddington limit include geometrical effects arising from the funneling of in-falling material along magnetic field lines.

While M82 X-2 was previously known as an X-ray source, it was not until an observation campaign to study the newly discovered supernova SN 2014J in January 2014 that X-2's true nature was uncovered. Scientists looking at data from the NuSTAR spacecraft noticed a pulsing in the X-ray spectrum coming from near the supernova in Messier 82. Data from the Chandra and Swift spacecraft was used to verify the NuSTAR findings and provide the necessary spatial resolution to determine the exact source. After combining the NuSTAR and Chandra data, scientists were able to discern that M82 X-2 emitted both an X-ray beam and continuous broad X-ray radiation.

Messier 82

Messier 82 (also known as NGC 3034, Cigar Galaxy or M82) is a starburst galaxy approximately 12 million light-years away in the constellation Ursa Major. A member of the M81 Group, it is about five times more luminous than the whole Milky Way and has a center one hundred times more luminous than our galaxy's center. The starburst activity is thought to have been triggered by interaction with neighboring galaxy M81. As the closest starburst galaxy to Earth, M82 is the prototypical example of this galaxy type. SN 2014J, a type Ia supernova, was discovered in the galaxy on 21 January 2014. In 2014, in studying M82, scientists discovered the brightest pulsar yet known, designated M82 X-2.

Steve Fossey

Stephen John Fossey is a British astronomer working at UCL Observatory, which is part of University College London (UCL). He is one of the three editors of The Observatory magazine.Fossey's research interests are in the interstellar medium, exoplanets and time-domain astronomy. He co-discovered the transit of the (previously-known) exoplanet HD 80606b (along with Ingo Waldmann and David Kipping) in 2009. Fossey also discovered supernova SN 2014J, the closest supernova for each for several decades, in January 2014.

Supernova

A supernova ( plural: supernovae or supernovas, abbreviations: SN and SNe) is a transient astronomical event that occurs during the last stellar evolutionary stages of the life of a massive star, whose dramatic and catastrophic destruction is marked by one final, titanic explosion. This causes the sudden appearance of a "new" bright star, before slowly fading from sight over several weeks or months or years.

Supernovae are more energetic than novae. In Latin, nova means "new", referring astronomically to what appears to be a temporary new bright star. Adding the prefix "super-" distinguishes supernovae from ordinary novae, which are far less luminous. The word supernova was coined by Walter Baade and Fritz Zwicky in 1931.Only three Milky Way, naked-eye supernova events have been observed during the last thousand years, though many have been seen in other galaxies. The most recent directly observed supernova in the Milky Way was Kepler's Supernova in 1604, but two more recent supernova remnants have also been found. Statistical observations of supernovae in other galaxies suggest they occur on average about three times every century in the Milky Way, and that any galactic supernova would almost certainly be observable with modern astronomical telescopes.

Supernovae may expel much, if not all, of the material away from a star at velocities up to 30,000 km/s or 10% of the speed of light. This drives an expanding and fast-moving shock wave into the surrounding interstellar medium, and in turn, sweeping up an expanding shell of gas and dust, which is observed as a supernova remnant. Supernovae create, fuse and eject the bulk of the chemical elements produced by nucleosynthesis. Supernovae play a significant role in enriching the interstellar medium with the heavier atomic mass chemical elements. Furthermore, the expanding shock waves from supernovae can trigger the formation of new stars. Supernova remnants are expected to accelerate a large fraction of galactic primary cosmic rays, but direct evidence for cosmic ray production was found only in a few of them so far. They are also potentially strong galactic sources of gravitational waves.Theoretical studies indicate that most supernovae are triggered by one of two basic mechanisms: the sudden re-ignition of nuclear fusion in a degenerate star or the sudden gravitational collapse of a massive star's core. In the first instance, a degenerate white dwarf may accumulate sufficient material from a binary companion, either through accretion or via a merger, to raise its core temperature enough to trigger runaway nuclear fusion, completely disrupting the star. In the second case, the core of a massive star may undergo sudden gravitational collapse, releasing gravitational potential energy as a supernova. While some observed supernovae are more complex than these two simplified theories, the astrophysical collapse mechanics have been established and accepted by most astronomers for some time.

Owing to the wide range of astrophysical consequences of these events, astronomers now deem supernova research, across the fields of stellar and galactic evolution, as an especially important area for investigation.

Ursa Major

Ursa Major (; also known as the Great Bear) is a constellation in the northern sky, whose associated mythology likely dates back into prehistory. Its Latin name means "greater (or larger) she-bear," referring to and contrasting it with nearby Ursa Minor, the lesser bear. In antiquity, it was one of the original 48 constellations listed by Ptolemy in the 2nd century AD. Today it is the third largest of the 88 modern constellations.

Ursa Major is primarily known from the asterism of its main seven stars, which has been called the "Big Dipper," "the Wagon," "Charles's Wain," or "the Plough," among other names. In particular, the Big Dipper's stellar configuration mimics the shape of the "Little Dipper." Its two brightest stars, named Dubhe and Merak (α Ursae Majoris and β Ursae Majoris), can be used as the navigational pointer towards the place of the current northern pole star, Polaris in Ursa Minor.

Ursa Major, along with asterisms that incorporate or comprise it, is significant to numerous world cultures, often as a symbol of the north. Its depiction on the flag of Alaska is a modern example of such symbolism.

Ursa Major is visible throughout the year from most of the northern hemisphere, and appears circumpolar above the mid-northern latitudes. From southern temperate latitudes, the main asterism is invisible, but the southern parts of the constellation can still be viewed.

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