observations of supernova remnants with veritas...veritas accumulated 2~3 times larger data for tev...
TRANSCRIPT
Observations of Supernova Remnants with VERITAS
Presented by Nahee Park
Thursday, May 8, 14
What do we want to learn?Are SNRs the main accelerators of the Galactic cosmic rays?
Efficiency of cosmic-ray acceleration?
Maximum energy that can be accelerated in SNRs?
Compiled data up to Jan. 2010 from CR database ( A.W.Strong et al, 2009 ICRC)Ackerman et al (2013)
Tycho
Morlino & Caprioli (2012)
Thursday, May 8, 14
What do we want to learn? (2)Study of the gamma-ray emissions from SNRs
Evolution of the SNRs as CR accelerators?
Difference depending on the environments & SNR types?
Resolving different components in SED?
Properties of escaping CRsCRs with higher energy escape first.
Possible high energy gamma-ray emissions from nearby MC?(e.g. W44 & W28)
Gamma-ray observations of SNRs provide a unique window - to study the acceleration & propagation of CRs - to study the environments & properties of SNRs
Thursday, May 8, 14
TeV SNRs
http://tevcat.uchicago.edu
IC 443
Tycho
Cas A
VER J2019+407
VER J2227+608
W51CW49B
MGRO J1908+06
in Northern sky
Thursday, May 8, 14
VERITAS SNR ProgramDeep observation of TeV SNRs
Cassiopeia A
Tycho
IC 443
Study of unidentified TeV sources with nearby SNRsVER J2019+407(γCygni)
MGRO J1908+06
VER J2227+608 (SNR G106.3+2.7)
Search for the discoveriesFermi SNR searching : W44, CTB109, etc
SNRs located nearby MC : VRO42.05.01, HB3, etc
Strong radio SNRs : W63, etc
Thursday, May 8, 14
Deep ObservationsEstimated results (calculated by Igor Telezhinsky)
Cass
iopeia
A
Tych
o
Thursday, May 8, 14
Deep ObservationsEstimated results (calculated by Igor Telezhinsky)
Cass
iopeia
A
Tych
o
Thursday, May 8, 14
IC 443MC interacting, nearby SNR
Two shells expanding to different density regions
OH masers
Distance ~ 1.5 kpc
PWN in the southern part
With TeV gamma-ray observations,Study CR diffusion
Morphology studies with deeper exposure
Estimate the flux from PWN
CXOU J061705.3+222127
Acciari et al (2009)
Ackerman et al (2013)
Thursday, May 8, 14
Cassiopeia AA historic, core-collapse SNR
Age : ~ 350 years, distance : ~ 3.4 kpc
Non-thermal X-ray emissions fromboth forward & reverse shocks
With TeV gamma-ray observations,Study the origin of gamma-ray emissions
Leptonic vs. hadronic
Contributions from reverse shock
Estimate the maximum energy of CRs
Yuan et al (2013)
Abdo et al (2010)
Thursday, May 8, 14
TychoA historical, Type Ia SNR
Age : ~440 yr, distance : 2~5 kpc
Exploded in relatively clean environment
Nearby MC in NE side
Hint of density gradient of ISM
Complicated structures in X-ray
Thin filaments, bright strips
With TeV gamma-ray observations,Determine the origin of the emission: MC vs. shell
Estimate the maximum energy of CRs
Study the acceleration theory in detail
e.g. Understanding a softer spectral index measured by Fermi-VERITAS
Acciari et al (2011)
Morlino & Caprioli (2012)
Thursday, May 8, 14
Tycho (2)Provide a laboratory to test various theoretical models
Thursday, May 8, 14
Tycho (2)Provide a laboratory to test various theoretical models
Thursday, May 8, 14
Observational StatusVERITAS accumulated 2~3 times larger data for TeV SNRssince the first reports of detections
Tycho
~ 140 hours ( from 67 hours )
Cassiopeia A
~ 100 hours ( from 22 hours )
Large zenith angle observation : increase of effective area for higher energy
IC 443
~ 90 hours ( from 37 hours )
Thursday, May 8, 14
Study of unidenti!ed TeV sourcesVER J2019+407
Coincide with NW shell of γCygni, Located within the Fermi cocoon
c.f. Fermi : extended emission from the entire remnant
MGRO J1908+06Partially coincide with SNR G40.5-0.5
Interaction of the pulsar wind with nearby molecular clouds or the SNR shock?
PWNe of PSR J1907+0602 & undetected pulsar?
VER J2227+608Coincide with SNR G106.3+2.7 & Milagro C4
PWN(PSR J2229+6114)/SNR(G106.3+2.7) complex?
Thursday, May 8, 14
Search for other TeV SNRsFermi-bright SNR search
W44
Search for SNRs nearby MC (w/ potential Fermi source)
HB3/W3 complex
VRO 42.05.01
CTB 109
Search for emissions from other FoVs3C396, 3C397, Kes79, HC40...
Thursday, May 8, 14
Future planLong term plan
What is the best way for VERITAS to contribute to SNR studies in next 3~5 years?
Collaboration with other gamma-ray experiments
Fermi
HAWC
Thursday, May 8, 14