1. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Circumstellar interaction of supernovae: inputs from radio and X-ray wave bands Poonam Chandra Joint Astronomy Programme Indian Institute of Science, Bangalore & Tata Institute of Fundamental Research, Mumbai,INDIA

2. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Plan of the talk Introduction Energetics of supernovae Explosion mechanism Classification Supernova-CSM interaction Shock formation Self similarity Production of radio and X-rays Study of CSM-SN interaction in radio bands SN 1993J (Plasma energetics from synchrotron cooling) SN 2003bg (Radio absorption mechanism) Study of CSM-SN interaction in X-ray bands SN 1995N (Progenitor constraints from Neon lines) SN 2002ap (Prompt X-rays) Conclusions

3. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar SUPERNOVA Death of a massive star Violent explosions in the universe Energy emitted (EM+KE) ~ 10 51 ergs. (To realise hugeness of the energy, the energy emitted in the atmospheric nuclear explosion is ~ 1 MT ≈ 4x10 22 ergs.)

4. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar  Enrich galaxy with heavy elements such as Iron, Calcium, Silicon, which are crucial to life.  Influence formation of new stars.  Are used to measure the geometry of the universe.  Result of the stellar and influence galaxy evolution.  Possible source of energetic cosmic rays. WHY SUPERNOVAE???????? SUPERNOVAE:

5. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar List of Publications (I) Chandra's tryst with SN 1995N Poonam Chandra, A. Ray, E. Schlegel, F. Sutaria, W. Pietsch 2005,To appear in ApJ 20 August 2005, v629 2 issue. Late time radio emission from SN 1993J at Meterwavelengths Poonam Chandra, A. Ray, S. Bhatnagar, 2004, ApJ, 612, 97 Baby supernovae through the looking glass at long wavelengths Poonam Chandra, Alak Ray 2004, Bull. Astron. Soc. of India, 32, 223. Synchrotron Aging and the Radio Spectrum of SN 1993J Poonam Chandra, A. Ray, S. Bhatnagar 2004, ApJL, 604, 97.

6. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar List of Publications (II) The nature of the prompt X-ray and radio emission from SN 2002ap F.K. Sutaria, Poonam Chandra, S. Bhatnagar, A. Ray 2003, A & A, 397, 1011. Radio studies of young core collapse supernovae Poonam Chandra, A. Ray, S. Bhatnagar 2002, Bull. Aston. Soc. of India, 30, 755. Implications of aging in young supernovae Poonam Chandra, A. Ray 2005, To appear in proceedings of '1604 - 2004 Supernovae As Cosmological Lighthouses', ASP conference series.

7. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Core collapse Supernovae Type II, Ib, Ic Neutron star or Black hole remains More massive progenitor (> 8 M Solar ) Found only in Spiral arms of the galaxy (Young population of stars) Thermonuclear Supernovae Type Ia No remnant remaining Less massive progenitor (4-8 M Solar ) Found in elliptical and Spiral galaxies Two kinds of supernova explosions The total energy emitted in core collapse SNe is ~ 10 53 ergs. But 99% energy is carried by neutrinos.

8. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Chemical explosives~10 -6 MeV/atom Nuclear explosives~ 1MeV/nucleon Novae explosionsfew MeV/nucleon Thermonuclear explosionsfew MeV/nucleon Core collapse supernovae100 MeV/nucleon Energy scales in various explosions

9. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar ProcessLength ScaleTime scale Collapse1000-3000 km~100 ms Shock revival100-300 km~ sec Shock breakout -- for BSG3 x 10 7 km6000 s -- for RSG5 x 10 8 km~ day Early inv-Comp10 9 -10 10 kmFew days Radiation from SN-CSM int. 10 10 -10 12 kmFew 10 yrs SN in ejecta dominated phase 10 10 -10 13 kmFew 100 yrs SN in sedav Taylor phase < 10 14 km100-1000 yrs Various timescales and lengthscales in SN processes

10. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Classification H (Type II) No H (Type I) Si (Type Ia) No Si (6150A o ) He (Type Ib) No He (Type Ic) (Various types- IIn, IIP, IIL, IIb etc.) Based on optical spectra

11. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar SN explosion centre Photosphere Outgoing ejecta Reverse shock shell Contact discontinuity Forward shock shell Radius Density Circumstellar matter Not to scale

12. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Shock Formation in SNe: Blast wave shock : Ejecta expansion speed is much higher than sound speed. Shocked CSM: Interaction of blast wave with CSM. CSM is accelerated, compressed, heated and shocked. Reverse Shock Formation: Due to deceleration of shocked ejecta around contact discontinuity as shocked CSM pushes back on the ejecta.

13. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Chevalier & Fransson, astro-ph/0110060 (2001)

14. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Self-Similarity in supernovae When distribution of flow variables remain similar to themselves The young SNe studied by us lie in Ejecta-dominated phase. where and Radiative losses are dynamically unimportant Chevalier (1982)

15. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Circumstellar Interaction Shock velocity of typical SNe are ~1000 times the velocity of the (red supergiant) wind. Hence, SNe observed few years after explosion can probe the history of the progenitor star thousands of years back.

16. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Radio emission from Supernovae: Synchrotron non-thermal emission of relativistic electrons in the presence of high magnetic field. X-ray emission from Supernovae: Both thermal and non-thermal emission from the region lying between optical and radio photospheres. Interaction of SN ejecta with CSM gives rise to radio and X-ray emission

17. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Radio emission is by energetic electrons in the presence of the high energy magnetic fields. Radio emission is absorbed either by free-free absorption from the circumstellar medium or synchrotron self absorption depending upon the mass loss rate, ejecta velocity and electron temperature, magnetic field. Both absorption mechanisms carry relevant information. Radio Emission in Supernovae

18. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Free-free absorption: absopriton by external medium Information about mass loss rate. Synchrotron self absorption: absorption by internal medium Information about magnetic field and the size.

19. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Plasma Energetics Information about the magnetic field Equipartition fraction (Magnetic energy density versus relativistic energy density) Evolution of equipartition fraction with time

20. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar X-ray emission from supernovae Thermal X-rays versus Non-thermal X-rays

21. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar X-rays from the shocked shell

22. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Inverse Compton scattering (non-thermal)

23. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar X-rays from the clumps in the CSM (thermal)

24. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar SN 1993J – 10 years old supernova SN 2003bg – 1 year old supernova Supernova interaction with the CSM in the radio bands

25. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Date of Explosion : 28 March 1993 Type : IIb Parent Galaxy :M81 Distance : 3.63 Mpc SN 1993J

26. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Giant Meterwave Radio Telescope 1420 MHz 610 MHz 50 MHz 150 MHz 235 MHz 325 MHz

27. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar GMRT Observations of SN 1993J Followed from 7 years to 10 years since explosion. Observing frequency bands: 1420, 610, 325, 235 MHz bands (20 cm, 50cm, 90cm, 125cm) Light curves at 1420, 610, 325, 235 MHz bands Simultaneous to near simultaneous spectra at 5 epochs Combined with VLA high frequencies spectra on day 3200 since explosion Followed from 7 years to 10 years since explosion. Observing frequency bands: 1420, 610, 325, 235 MHz bands (20 cm, 50cm, 90cm, 125cm) Light curves at 1420, 610, 325, 235 MHz bands Simultaneous to near simultaneous spectra at 5 epochs Combined with VLA high frequencies spectra on day 3200 since explosion

28. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar 235 MHz map of FOV of SN1993J 1993J M81 M82

29. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Free-free model of Weiler et al. 2002, ARA&A, 40, 387

30. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar External Free- free absorption model based on high frequency light curves, incompatible with low frequency light curves. NOT STRAIGHT EXTRAPOLATION

31. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Observations of SN 1993J at meter and shorter wavelengths Date of observation Frequency GHz Flux density mJy Rms mJy Dec 31, 010.23957.8 ± 7.62.5 Dec 30, 010.61947.8 ± 5.51.9 Oct 15, 011.39633.9 ± 3.50.3 Jan 13, 021.46531.4 ± 4.282.9 Jan 13, 024.88515.0 ± 0.770.19 Jan 13, 028.447.88 ± 0.460.24 Jan 13, 0214.974.49 ± 0.480.34 Jan 13, 0222.492.50 ± 0.280.13 VLA GMRT

32. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Frequency (GHz) Flux density (mJy) GMRT VLA Composite radio spectrum on day 3200  = 0.6

33. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Synchrotron Aging Due to the efficient synchrotron radiation, the electrons, in a magnetic field, with high energies are depleted.

34. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar N(E) E N(E)=kE - . Q(E)  E -  steepening of spectral index from  =(  -1)/2 to  /2 i.e. by 0.5.

35. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Frequency (GHz) Flux density (mJy) GMRT VLA break =4 GHz R= 1.8x10 17 cm B= 38±17 mG  = 0.6 Composite radio spectrum on day 3200  2 = 7.3 per 5 d.o.f.  2 = 0.1 per 3 d.o.f.

36. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Synchrotron Aging in SN 1993J Synchrotron losses Adiabatic expansion Diffusive Fermi acceleration Energy losses due to adiabatic expansion Ejecta velocity Size of the SN

37. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Upstream velocity Downstream velocity Spatial diffusion coefficient of the test particles across ambient magnetic field Particle velocity Energy gain due to diffusive Fermi acceleration

38. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Forand Break frequency........ (Fransson & Bjornsson, 1998, ApJ, 509, 861)

39. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Magnetic field independent of equipartition assumption & taking into account adiabatic energy losses and diffusive Fermi acceleration energy gain B=330 mG. (Chevalier, 1998, ApJ, 499, 810) Crab in equipartition?

40. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Break frequency evolution with time Early epochs (~20 yrs) Later epochs (>20 yrs) Break frequency decrease with time if acceleration is important otherwise increase with time...

41. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Days since explosion Size in 10 16 cm Size Evolution of the SN

42. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Magnetic Field Evolution

43. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Synchrotron self absorption is the dominant mechanism for the turn over in the spectra at all epochs. Comparison of VLBI size vs SSA size

44. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar SN 2003bg Discovery : 25 Feb 2003 Type: Ic Parent Galaxy: MCG -05-10-015 Distance: 19 Mpc

45. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Observations of SN 2003bg at meter and shorter wavelengths Date of observation Frequency GHz Flux density mJyRms mJy Feb 08, 040.325  3.2 1.6 Feb 05, 040.6194.12 ± 1.080.3 Feb 02, 041.28024.3 ± 0.20.2 Feb 08, 041.46523.88 ± 0.4- Feb 08, 044.88530.88 ± 0.08- Feb 08, 048.4418.96 ± 0.07- Feb 08, 0414.979.65 ± 0.17- Feb 08, 0422.56.56 ± 0.08- Feb 08, 0444.32.23 ± 0.26- GMRT VLA Soderberg & Kulkarni

46. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Model for radio emission External absorption (Free-free absorption) Internal absorption (Synchrotron self absorption) External absorption (Free-free absorption) Internal absorption (Synchrotron self absorption) Signature - optically thick part i.e. low frequency external absorption 5/2 decay internal absorption

47. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar SSA FFA

48. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Internal absorption (Synchrotron Self- Absorption) at work. Discard External free-free absorption

49. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar ParametersUnitsSN 2003bgSN 1993J Spec. index3.063.18 Mag. FieldGauss0.181.48 Radius10 16 cm9.95.9 Implied Velocity 10 4 km/s3.281.73 Comparison of SN 2003bg with SN 1993J

50. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar SN 1993J (IIb) vs SN 2003bg (Ic) SN 1993J  size of the SN: 5.9 x 10 16 cm  Expansion speed 17,000 km/s  Magnetic field 1.5 G SN 2003bg  size of the SN: 9.9 x 10 16 cm  Expansion speed 33,000 km/s  Magnetic field 0.18 G Comparison Roughly twice 10 times lower

51. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Conclusions SN 1993J  GMRT+VLA spectrum: synchrotron cooling determination of magnetic field and plasma energy ratio.  Magnetic energy density 10,000 times more than relativistic energy density.  Need of independent models at low frequencies SN 1993J  GMRT+VLA spectrum: synchrotron cooling determination of magnetic field and plasma energy ratio.  Magnetic energy density 10,000 times more than relativistic energy density.  Need of independent models at low frequencies SN 2003bg GMRT+VLA spectrum: Discarding free-free absorption model against synchrotron self absorption model SN 2003bg GMRT+VLA spectrum: Discarding free-free absorption model against synchrotron self absorption model

52. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar SN 2002ap – Caught few days old by XMM-Newton SN 1995N – Caught 9 year old by Chandra Supernova interaction with the CSM in the X-ray bands

53. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar SN 1995N A type IIn supernova Discovered on 1995 May 5 Parent Galaxy MCG-02-38- 017 (Distance=24 Mpc)

54. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Excellent Case: SN 1995N Previous X-ray observations: ROSAT HRI: Aug 1996 ROSAT HRI: Aug 1997 ASCA: Jan 1998 Flux decline by 30% in one year and rises by factor of 2 in 6 months!!!!!!!!

55. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar ROSAT BAND (0.1-2.4 keV) ASCA BAND (0.5-7.0 keV)

56. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar We observed SN1995N with Chandra telescope as a part of Guest Observer on March 28, 2004. Observations with Advanced CCD Imaging Spectrometer (ACIS-S) Total exposure 55.74 ksec.

57. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Chandra X-ray observatory

58. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar SN 1995N Chandra observations Total counts758 counts Temperature2.35 keV Absorption column Depth1.5 x 10 -21 cm -2 0.1-2.4 keV Unabsorbed flux0.6-1.0 x 10 -13 erg cm -2 s -1 0.5-7.0 keV Unabsorbed flux0.8-1.3 x 10 -13 erg cm -2 s -1 Luminosity (0.1-10 keV)2 x 10 40 erg s -1

59. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Bremsstrahlung (kT=2.21 keV, N H =2.46 x 10 21 /cm 2. ) Gaussians at 1.03 keV (N=0.34 +/- 0.19 x 10 -5 ) and 0.87 keV (N=0.36 +/- 0.41 x 10 -5 ) NeX NeIX?

60. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar NeX NeIX 99.9% 90% 67% 99.9% 90% 67%

61. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Constraining the progenitor mass Compatible with 15 solar mass progenitor star Luminosity of Neon X line Cascade factor Emissivity of neon X line Number density of neon is ~ 600 cm -3. Fraction of NeXI to total Neon

62. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Chandra image

63. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar ASCA Image

64. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar ROSAT BAND (0.1-2.4 keV) ASCA BAND (0.5-7.0 keV)

65. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar ROSAT BAND (0.1-2.4 keV) ASCA BAND (0.5-7.0 keV)

66. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar X-ray emission most likely by the reverse shock. Cool shell seem to form after a reverse shock (shown due to the enhanced absorption which is not present in other X- rays sources in the galaxy.

67. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Summary of SN 1995N results: Evolution of the spectrum. Neon line emission seen. Neon mass consistent with a progenitor of 15 M sun Most likely Reverse shock model responsible for X- ray emission Observed column depth is more than obtained from Galactic extinction methods. Cooled shell ahead of reverse shock

68. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Why is SN 2002ap interesting? One of the closest supernova (d=7.3 Mpc) Large explosion energy ~ 4-10x 10 51 ergs A type Ic supernova Date of discovery Jan 29.2,2002 by Y. Hisrose. Explosion date Jan 28, 2002. Parent Galaxy NGC628 (M74). Distance =7.3 Mpc. Devoid of H, He core. Can be probed nearer to the central engine. Possible association with GRBs of Ic SNe. Such as SN1998bw/GRB980425 and SN2003dh/GRB030329.

69. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar

70. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar X-ray observations of SN 2002ap with XMM- Newton in view of pre-SN field Chandra Observations Observed with XMM-Newton Epic-CCDs for exposure time ~34ks between Feb 2.03-2.42, 2002. Pre-SN field observed by Chandra on Jun,01 and Oct,01 and found a nearby source 14.9 ” away from the SN posn. LHS is XMM image of SN field and green circle shows SN position. RHS panel shows the pre-SN image. A source is seen within the circle.

71. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Extrapolation from Radio to X-ray: Direct extrapolation of radio flux to X-ray yields 58 picoJy at 1keV which corresponds to flux of 5x10 -16 erg s -1 cm -2. Too low to account for. Free-free emission: It could account for the observed X-rays but it predicts a very high temperature extended to long flat compton tail upto ~100 keV energies (see fig. below). Not present.

72. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Compton Boosting of Optical Photons: X-rays can be achieved by the repeated scatterings of optical photons with hot electrons. The two fluxes are related by (Fransson, 1982) where the optical depth of electrons is and energy index  is

73. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Repeated scattering of optical photons can account for the prompt X-ray emission on day 5 in SN 2002ap.

74. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Comparison of SN 2002ap with a GRB associated type Ic (SN 1998bw) SN and a normal type IIb SN (SN 1993J) Comparison of SN 2002ap with SN 1993J and SN 1998bw. The table gives the best fit SSA parameters and equipartition radius.

75. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Conclusions of the thesis First observational evidence of synchrotron cooling break in SN 1993J SN 1993J magnetic field is not in equipartition with that of relativistic energy density (U B /U Rel =10,000) (Crab in equipartition. Evolution of plasma??)

76. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Synchrotron self absorption is important in SN1993J and SN 2003bg Expansion speeds in plasma are widely different for different supernovae. Conclusions of the thesis

77. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminar Detection of Neon X and Neon IX in SN 1995N Chandra spectrum. Neon mass is compatible with the 15 solar mass progenitor star. Inverse Compton scattering of photospheric photons by hot electrons responsible for prompt X- rays in SN 2002ap Conclusions of the thesis

78. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminarAcknowledgements Alak Ray Sanjay Bhatnagar Kurt Weiler Chris Stockdale Alicia Soderberg Shri Kulkarni Eric Schlegel Firoza Sutaria

79. Poonam ChandraIndian Institute of Science 24 June 2005 Ph.D. synopsis seminarTHANKS!!!!