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Research Topic: Supernovae. Chelsea Braun. Credit: Artist illustration ESO, http ://www.universetoday.com/wp-content/uploads/2006/12/2006-1130supernova.jpg. Overview. What is a Supernova? Types of Supernovae Supernovae in NGC 4088 The Questions Research Paper 1: Supernova
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Research Topic: Supernovae Chelsea Braun Credit: Artist illustration ESO, http://www.universetoday.com/wp-content/uploads/2006/12/2006-1130supernova.jpg
Overview What is a Supernova? Types of Supernovae Supernovae in NGC 4088 The Questions Research Paper 1: Supernova Research Paper 2: NGC 4088 Relevance
What is a Supernova? (Carroll BW, Ostlie DA. 2007) • A supernova is an exploding star • A large explosion of energy that spews out gas and dust into space • 100x more energy than the sun will produce over its main sequence life • Shine brightly for many weeks then fade in months or possibly years
Types Of Supernovae Credit: NASA, www.en.wikipedia.org/wiki/File:Hst_SN_1987A_20th_anniversay.org Credit: www.dujs.dartmouth.edu/wp-content/uploads/2008/05/picture-16.png (Carroll BW, Ostlie DA. 2007) • Supernovae are classified by their emission spectra lines • There are two classes: • Type I • Type II
Type I (Carroll BW, Ostlie DA. 2007) • Contain NO hydrogen emission lines • There are 3 subclasses of Type I: • Type Ia • Shows strong Si II lines at 615nm • Type Ib • Shows strong helium lines • Type Ic • shows the absence of helium lines
Type II (Carroll BW, Ostlie DA. 2007) • Contains hydrogen emission lines • Found in the massive star forming regions of spiral and irregular galaxies • Thought to originate from massive stars
Supernovae classification Credit: http://hyperphysics.phy-astr.gsu.edu/hbase/astro/snovcn.html#c3
Supernovae in NGC 4088 (SIMBAD database) Credit: Bonnie Fisher and Mike Shade/Adam Block/NOAO/AURA/NSF • NGC 4088 is a weakly barred spiral galaxy SAB(rs)bc • 2 recorded supernova • Both Type II
The Questions Is it possible to detect any of these supernovas in the images generated at GAO? What does a supernova tell us about a galaxy? What types of supernovas appear in what galaxies and where?
Research Paper 1: Supernova (Van Dyk SD, Hamuy M, Filippenko AV. 1996) Supernovae and Massive Star Formation Regions Schuyler D. Van Dyk, Mario Hamuy, Alexei V. Filippenko • What were the authors studying? • Finding the degree of association between Type Ib/c and Type II supernovas with HII regions in spiral and irregular galaxies • Determining if there is any difference between Type Ib/c and Type II progenitors
Research Paper 1: Supernova (Van Dyk SD, Hamuy M, Filippenko AV. 1996) • How did they study it? • Detected emission lines from Hα that arise from photons emitted by hot, massive young stars (this detects the HII regions in question) • Compared SN locations with center of HII regions • Details on the data that was used?
Research Paper 1: Supernova (Van Dyk SD, Hamuy M, Filippenko AV. 1996) • Conclusion? • Degree of association of Type Ib/c and II with HII are not significantly different: both are associated with massive star forming regions • Supports that the difference between Ib/c and II are due to binarity and interaction in SN Ib/c progenitor stellar systems • Future Studies? • Complementary studies with higher resolution using the Hubble Space Telescope allowing for a further detailed statistical analysis
Research Paper 2: NGC 4088 (Blanton EL et al. 1995) Observations of the Type II-P SN 1991G in NGC 4088 Elizabeth L. Blanton, Brian P. Schmidt, Robert P. Kirshner, Charles H. Ford, Frederick R. Chromey, William Herbst • What were the authors studying? • location • SN type classification • Explosion date • Duration time • Ni output
Research Paper 2: NGC 4088 (Blanton EL et al. 1995) • How did they study it? • Photometry and spectroscopy • Distance • Explosion date • Light curve analysis • Magnitude over time • Classifying type of SN II as a plateau
Research Paper 2: NGC 4088 (Blanton EL et al. 1995) • Details on the data used • Wesleyan University’s Van Vleck Observatory • 0.6m Cassegrain Telescope • Thermoelectrically cooled PM512 CCD • Exposure: 100 sec, 3-5 exposures per filter • Double beam spectrograph • 5m Hale Telescope • Multiple mirror telescope • Red channel spectrograph
Research Paper 2: NGC 4088 • Conclusion: • Classified Type II-P • Plateau ~120 days • Compared to other SN and might indicate a relation between Ni and energy output
Relevance • Research paper 1: • supernovae of Type II and Type Ib/c develop massive star forming regions • A supernova in a galaxy of these types would then be a good indicator of the star forming regions • Research paper 2: • From the light curves, the images at GAO would not be able to detect this supernova, as it should be too faint • Look into the detection of the more recent supernova of 2009
Citations Blanton EL et al. 1995. Observations of the Type II-P SN 1991G in NGC 4088. AJ. 110: 2868-2875 Carroll BW, Ostlie DA. 2007. An Introduction to Modern Astrophysics. Pp. 524-550. San Francisco: Pearson Education, Inc. 2nd ed. SIMBAD database, CDS, Strasbourgh, France Aladin Sky Atlas, CDS, Strasbourgh, France Van Dyk SD. 2009. What are Supernovae?. Last visited: Mar 1, 2012. http://spider.ipac.caltech.edu/staff/vandyk/supernova.html Van DykSD, Hamuy M, Filippenko AV. 1996. Supernovae and Massive Star Formation Regions. AJ. 111: 2017-2027
SN1991G (SIMBAD database) Credit:Aladin • Occurred 1991 • Type II • location: • 48.1” W and 9.6” S of center of NGC 4088
SN2009dd (SIMBAD database) Credit: Aladin • Occurred April 13, 2009 • Type II • location: • 1” W and 3” S of center of NGC 4088