Chelsea Braun Credit: Artist illustration ESO, content/uploads/2006/12/ supernova.jpg

 What is a Supernova?  Types of Supernovae  Supernovae in NGC 4088  The Questions  Research Paper 1: Supernova  Research Paper 2: NGC 4088  Relevance

 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 (Carroll BW, Ostlie DA. 2007)

 Supernovae are classified by their emission spectra lines  There are two classes: Type I Type II (Carroll BW, Ostlie DA. 2007) Credit: content/uploads/2008/05/picture-16.png Credit: NASA, ipedia.org/ wiki/File:Hs t_SN_1987A _20th_anniv ersay.org

 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 (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 (Carroll BW, Ostlie DA. 2007)

Credit:

 NGC 4088 is a weakly barred spiral galaxy SAB(rs)bc  2 recorded supernova Both Type II Credit: Bonnie Fisher and Mike Shade/Adam Block/NOAO/AURA/NSF (SIMBAD database)

 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?

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 (Van Dyk SD, Hamuy M, Filippenko AV. 1996)

 How did they study it? Detected emission lines from H α 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?

 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 (Van Dyk SD, Hamuy M, Filippenko AV. 1996)

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 (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 (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 (Blanton EL et al. 1995)

 Conclusion: Classified Type II-P Plateau ~120 days Compared to other SN and might indicate a relation between Ni and energy output

 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

 Blanton EL et al Observations of the Type II-P SN 1991G in NGC AJ. 110:  Carroll BW, Ostlie DA An Introduction to Modern Astrophysics. Pp San Francisco: Pearson Education, Inc. 2 nd ed.  SIMBAD database, CDS, Strasbourgh, France  Aladin Sky Atlas, CDS, Strasbourgh, France  Van Dyk SD What are Supernovae?. Last visited: Mar 1,  Van Dyk SD, Hamuy M, Filippenko AV Supernovae and Massive Star Formation Regions. AJ. 111:

 Occurred 1991  Type II  location: 48.1” W and 9.6” S of center of NGC 4088 (SIMBAD database) Credit:Aladin

 Occurred April 13, 2009  Type II  location: 1” W and 3” S of center of NGC 4088 (SIMBAD database) Credit: Aladin