Transcript Research Topic: Supernovae

Credit: Artist illustration ESO, http://www.universetoday.com/wpcontent/uploads/2006/12/2006-1130supernova.jpg
Chelsea Braun
 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
Credit:
NASA,
www.en.wik
ipedia.org/
wiki/File:Hs
t_SN_1987A
_20th_anniv
ersay.org
Credit: www.dujs.dartmouth.edu/wpcontent/uploads/2008/05/picture-16.png
(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
(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: http://hyperphysics.phy-astr.gsu.edu/hbase/astro/snovcn.html#c3
 NGC
4088 is a weakly
barred spiral galaxy
SAB(rs)bc
 2 recorded supernova
• Both Type II
(SIMBAD database)
Credit: Bonnie Fisher and Mike Shade/Adam
Block/NOAO/AURA/NSF
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 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?
(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
(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. 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 Dyk SD, Hamuy M, Filippenko AV. 1996. Supernovae and
Massive Star Formation Regions. AJ. 111: 2017-2027




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