Wide field X (& UV ?)
Identify transients, distribute alerts
Candidate X (&UV)-transients• SN breakouts• XRF’s• LL GRBs• Unknown (eg BH-Stellar disruptions)?
Early SN emission
• SN shock is radiation mediated at the envelope
• Outer (10-3Msun) heated to ~keV
• Shock emergence accompanied by thermal X-rays
• Post breakout expansion early UV emission
• Wind - Breakout may take place within the wind - Ejecta/wind interaction non-thermal X,
radio
Breakout X-rays: a simple model• At =c/vs:
• Optically thick wind, ~1 breakout:
• EX, T R, vs ; Consistency: t~R/c.
• Ejecta/Wind Non-T X-rays:
keV.
/2.0erg,
/102
,/
2.0/v
5.01205.0
Sun
2.0
BO7.1
124.0Sun
6.046
BO
3.0124.0
Sun
6.0
maxs,maxs,
5151
51
RMM
ETR
MM
EE
RMM
Ec
keV.1.0erg,103 4/112
3BO
212
446BO
RTRE
.s
erg,min10
3/247,3/1
42,40
synIC,
day
day1,1, t
EtLL k
SNee
XRO 080109-SN 2008D
• XRO: EX~3x1046erg, R~ct~1012cm (~1)
R*~1011cm Wind, mdot~few.
• Late non-T X (LX~1040td-0.7erg/s)+ radio
mdot~1 (@ 1015cm) wind + 1047erg, ~0.3 shell
• T=0.1keV? No! Non-thermal, dlog n/dlog E~ -2
• Jets? Or- Non-LTE X-rays in fast (v/c>0.1) breakouts:
keV.)2.0/(10
,/
2.0/v
4maxs,sBO,
3.0124.0
Sun
6.0
maxs,maxs,51
T
RMM
Ec
[Kat & Budnik 10]
Some implications
• XRO 080109 may be SN 2008D breakout
• For reasonable explosion parameters, WR & BSG progenitors produce fast breakouts non-thermal XRO’s up to 10’s to 100’s keV
• New type of SN triggerAccurate timing (hr models, , GW)EX, T R, vs
LL-SN-GRBs: E~1049erg, h<300keV, smooth L(t)–
Jets or EK~1049.5 erg, ~0.8 breakouts? Consistent with properties of 980425/SN1998b, 031203/SN2003lw, 060218/SN2006aj; 98bw late radio + X: now jet, EK~1049.5 erg, ~0.8 shell;
Challenges: EK(~0.8)/EK,tot~10-2 [Anisotropy, Failed Jet?].
X-ray: fluxes & rates
• 50SN/yr to 30Mpc• SN BO’s:
dist. not known Lower threshold E? 08D based rate (95%) > 10-3/L*yr~0.1 CC SN rate
• LL GRBs: EX~1048.5erg
(??) ~10-5/L*yr~1/yr out to 100Mpc
• ~10keV XRF’s: EX>~1048erg
(??) ~10-6/L*yr~ 0.1/yr out to 100Mpc
• ?? MBH Stellar disr.: 0.01Msunc2, 105(M/108Msun)s 1047erg/s
keV.)2.0/(10
s,30/erg/s,10erg,10
4maxs,sBO,
12230
7.0125.8
BOX,46
BOX,
T
RcRD
RfE
X-ray: Detectors
Required:• ~ 1• f < 10-9 erg/s (~10s)• ~ follow up FOV
The UFFO Pathfinder
arXiv:0912.0773
Summary- X
• Identify transients, distribute alerts Required: ~ 1, f < 10-9 erg/s (~10s), ~ follow up
FOV
• Candidate X (&UV)-transients * SN breakouts: New SN trigger, Accurate timing (hr models, , GW); EX, T R, vs
* XRF’s, LL GRBs: Sources, SN-connection, physics * Unknown (eg BH-Stellar disruptions)
UV transients
• Best resource is GALEX, not systematically surveyed so far
• Two classes of events receive attention: UV shock breakouts and tidal disruption flares
• Contamination by stars and AGN is a major issue
Early UV/Optical emission
• Rapid post-breakout expansion Adiabatic cooling, photosphere penetration
• t>R*/vBO Predictions:
• Measure R ( from T), EK (@ m/M~0.003)
• Complications: Extinction, opacity E.g. No of H recombination @ 1eV Constrain envelope composition
serg/cm10~erg/s,/
/10~
eV,/1
22
Mpc30
1211UV
1/3-day127.0
Sun
9.08.042
bol.
1/2-day
4/112
27.0eff.
51
D
RftR
MM
EmL
tRmT
pT
pT
2008D: Determine R* & Reddening
Scaling t, f:
etFtftT
T
tT
tT
r
Dttf
tTtttT
)(),()()(
)()],(,[
~
)()],([5
col.
0
4
phot.
col.
2
phot.
col.0col.
[Rabinak 10]
2008D- UV summary
• Early UV/O: R*=1011cm,
He with C/O Relative extinction curve, EB-V=0.6
E51/(M/Msun)~0.8 (assuming AV (EB-V))
• Later light curve: 0.8<E/M<1.3
~30% C at 20,000km/s 0.4<EB-V<0.8
Progenitor models: 0.9<R*/1011cm <1.5
[Rabinak 10]
[Mazzali et al. 08, Tanaka et al. 09]
[Mazzali, priv. comm.]
[Soderberg et al. 08]
[Tanaka et al. 09][Modjz et al. 09]
UV/O model[Tanaka et al. 09]
UV breakout rates (based on Gezari 2008, GALEX)
• GALEX expected rate (optimistic?) is 2 deg-1 y-1
• If we scale the GALEX area by ~103, we can expect >10 events y-1 even if the sensitivity is 102 less.
• The observed signals have UV flux~host, so confusion with (even mildly) variable sources is an issue unless additional information is available
• A combined UV survey+optical SN survey like PTF will be powerful to get retrospective measurements
Tidal disruption flares
• A star disrupted and accreted by a dormant supermassive black hole is expected to result in a UV/X flare, several months long.
• Several events claimed based on wide-field X (ROSAT) and UV (GALEX)
• Major issue is confusion with AGN.
UVFs
• Speculative: the end of the GRB-XRF sequence would be very soft flares (UVFs).
• Here, and in all other “unknowns” confusion with stars and AGN is a formidable obstacle.
UV - summary
• Best resource is GALEX, not systematically surveyed so far, most parameters unknown
• UV shock breakouts should be accessible to wide-field, moderately sensitive instruments
• Combination with X or optical may be powerful• Contamination by stars and AGN is a major
issue
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