Early and Late Prompt emission Gabriele Ghisellini INAF-Osservatorio Astronomico di Brera - Italy + UHECRs and Magnetars with the help of D. Burlon, A. Celotti, C. Firmani, F. Fraternali, G. Ghirlanda, D. Lazzati, L. Nava, M. Nardini, F. Tavecchio

Very early prompt: Precursors Study of all Swift GRBs with z Initial pulse, weaker and separated from the prompt (i.e. BAT flux below bkg level) Precursors in 15% Burlon+ astro-ph/

“Precursors” Very long  t Double Burlon+ 2008, astro-ph/

Not softer, not harder than the rest of prompt Very energetic (factor ~3 less than total) No correlation with delay time >40s15-40s<15s Slope Main Prompt Slope Precursor Energy Main Prompt Energy Precursor They look like the first pulse of the prompt, not a separated component. Why  t so long?

Late activity

X-ray and optical often behave differently ~same spectrum TATATATA Is this “real” afterglow? i.e. external shock? X-ray

Nardini et al., in prep. Optical X-rays TATATATA TA?TA?TA?TA? W h a t i s T A ?

Early (normal) prompt: Early (normal) prompt:  >>1 /  j Late prompt: Late prompt:  >1 /  j Late prompt: Late prompt:  =1 /  j Late prompt: Late prompt:  <1 /  j ”real” after- glow Ghisellini et al Strong, erratic Smooth After the early prompt, the central engine decreases energy and decreases  monotonically R~10 13 cm

Early (normal) prompt: Early (normal) prompt:  >>1 /  j Late prompt: Late prompt:  >1 /  j Late prompt: Late prompt:  =1 /  j Late prompt: Late prompt:  <1 /  j ”real” after- glow Ghisellini et al R~10 13 cm TATATATA T jet

 ~ t -   /2 t-2t-2t-2t-2 t-3t-3t-3t-3 Time Flux M out ~ t -(      ) /2 TATATATA L   M out ~ t -  

 ~ t -   /2 t-2t-2t-2t-2 t-3t-3t-3t-3 Time Flux M out ~ t -(      ) /2 Long lasting engine with two-phase accretion? 1: Very dense torus, large B-field, erratic. 2: Less dense material, smaller B-field, smoother accretion – Fallback? TATATATA L   M out ~ t -   L~ M accr ? Very cheap

MacFadyen t -5/3 M from fallback

Zhang Woosley Heger Time [s] Fallback lasts for quite a long time M from fallback

Lazzati t -5/3 From averaging the luminosity of flares in different GRBs

Lazzati t -5/4 From averaging the luminosity of flares in different GRBs

~70 Swift GRBs with z

t -5/3

t -5/4

SEDs vs light curvesSEDs vs light curves Tests Log F Log F Log Log optical X-rays

SEDs vs light curvesSEDs vs light curves Some GRBs with no plateau: achromatic breaks?Some GRBs with no plateau: achromatic breaks? Tests

SEDs vs light curvesSEDs vs light curves Some GRBs with no plateau: achromatic breaks?Some GRBs with no plateau: achromatic breaks? Late ‘jump’ in X-ray light-curves revealing real X-ray afterglowLate ‘jump’ in X-ray light-curves revealing real X-ray afterglow Tests TATATATA Jump=end of late prompt Time X-ray Flux

UHECRs, Spiral Galaxies and Magnetars with Ghirlanda, Tavecchio, Fraternali, Pareschi astro—ph/

27 Auger Events >57 EeV Auger events 1 EeV=10 18 eV The Auger collaboration, 2007, Science

CenA Virgo AGNs from VC-V catalogue If the Galactic plane is excluded, 19 out of 21 events do correlate Auger events The Auger collaboration, 2007, Science

HIPASS: ~5000 HI emitting galaxies (21 cm) GG+, 2008

Weight for flux and Auger exposure

~72%

Cut in distance

Cut in luminosity

Virgo Centaurus

It is not Cen A, it is the Centaurus cluster (>40 Mpc)

100 Mpc

F Auger ~ erg cm 2 s -1 Flux for E>57 EeV Easy for AGNs (but they are radio-quiet… no  ) Long `BATSE’ GRBs (too distant) Short `BATSE’ GRBs (flux not enough) Giant Flares of Magnetars (flux not enough) Newly born, fastly spinning Magnetars (!!!, but went unobserved by BATSE) Progenitors

Campana et al BB Flux Opt-UV GRB ???

Very long, soft, underluminous, nearby (145 Mpc)Very long, soft, underluminous, nearby (145 Mpc) It could not have triggered BATSEIt could not have triggered BATSE Proposed to be a newborn magnetar (Soderberg+ 2007; Toma+ 2007)Proposed to be a newborn magnetar (Soderberg+ 2007; Toma+ 2007) Right rateRight rate

Conclusions Precursors? Same as prompt  just first pulse. Why so long quiescent times?Precursors? Same as prompt  just first pulse. Why so long quiescent times? Late prompt with decreasing power and Late prompt with decreasing power and  T A is very easily explainedT A is very easily explained Fallback is long  late prompt “forever”Fallback is long  late prompt “forever” UHECRs correlate with spirals  newly born magnetars? If so, new class of GRBs (2 per yr all sky): similar to GRB : soft, very long, underluminous+SNUHECRs correlate with spirals  newly born magnetars? If so, new class of GRBs (2 per yr all sky): similar to GRB : soft, very long, underluminous+SN

Very energetic

Nardini et al., in prep. X-rays Optical