GLAST LAT Project

DC2 Closeout Workshop, GSFC, 31 May-2 June 2006 1

Sky Model for DC2:Sky Model for DC2:Extragalactic & Extragalactic &

Miscellaneous SourcesMiscellaneous Sources

Gamma-ray Large Gamma-ray Large Area Space Area Space TelescopeTelescope

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CreditsCredits

• Advice from Diego Torres on galaxies and galaxy clusters.• Paolo Giommi and Jim Chiang for AGN populations

(luminosity/redshift distributions)• Gino Tosti for blazar lightcurves.• Nicola Omodei for GRB simulation code• Luis Reyes for implementing EBL attenuation models.• Valerie Connaughton – GBM simulations

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Extragalactic Gamma-ray sourcesExtragalactic Gamma-ray sources

• Galaxy Clusters• Galaxies• Active Galactic Nuclei• Gamma-Ray Bursts• Hard transient (PBH)• Extragalactic background light

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Galaxy clustersGalaxy clusters

• Motivated by Reimer etc al. (2003, ApJ, 588, 155)

– Fluxes are chosen to be near the EGRET limits

• Modeled as point sources with power law index of -2.1.

• The redshifts are small, and assumed to be zero in the DC2 simulation.

– Coma, flux = 3.177e-08 cm-2 s-1

– Oph, flux = 1.383e-08 cm-2 s-1

– Perseus, flux = 3.177e-08 cm-2 s-1

– Virgo, flux = 3.972e-08 cm-2 s-1

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GalaxiesGalaxies

– LMC - extended source using spatial model developed by Sreekumar (Private communication). Flux was 1.42e-7 cm^-2 s^-1

– SMC - from Pavlidou and Fields 2001, ApJ, 558, 63 – M31 – with EGRET upper limit (1.0e-8, Pavlidou and Fields

2001)– M82 – Using most optimistic prediction from Blom et al.

1999, ApJ, 516, 744, spectral shape is from fig 1 of that paper.

– NGC 253 – Using the most optimistic prediction from Blom et al 1999.

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AGNAGN

• AGN – 104 high confidence blazar identifications of 3EG sources from 2003 and 2004 papers by Soward-Emmerd, Romani etc al and high confidence 3EG blazars from the 3rd catalog.

• 1005 AGN generated using package developed by Paolo Giommi (see Jim Chiang’s talk for details on redshift and flux distributions).

• All 104 EGRET blazars and the brightest 100 Giommi blazars were defined as variable sources, the remaining 905 Giommi blazars were steady sources.

• ~20 of the Giommi blazars were moved to locations and assigned the redshift of known AGN.

• B3 1428+422 (z=4.72) was 42’ away from 1ES 1426+428.

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AGNAGN

• 204 blazars were assigned lightcurves (see Gino Tosti’s talk for details).– Each blazar was fit as a broken power-law– There were two classes

• Highly variable, low break energy assigned to FSRQ’s and LBL

• Less variable, higher break energy assigned to HBLs.– The break energy, and gamma-gamma2 (the difference

between the two power-law indices) did not vary with time for a given blazar.

GLAST LAT Project

DC2 Closeout Workshop, GSFC, 31 May-2 June 2006 8

AGNAGN

• Some examples

0210-5055, Ebreak = 181 MeV Mrk 421, Ebreak = 1047 MeV

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Gamma-Ray BurstsGamma-Ray Bursts

• 132 GRB simulated over 4 pi

• 64 triggered the GBM, the remainder did not trigger due to:

– Earth occultation

– SAA passages

– Threshold cut of 6e-8 erg cm-2.

– Small bug in GRB simulation software which caused input files for GBM simulation to not be produced for some bursts (~5 GRB).

• GBM statistical uncertainty

– Inversely proportional to the maximum intensity of the burst as measured on a 0.25 sec timescale in the 2 brightest detectors and cosine corrected. It was a Gaussian distribution.

• GBM systematic uncertainty

– 2 degree (1 sigma) assumed to be independent of statistical error/brightness and distributed as a Gaussian.

GLAST LAT Project

DC2 Closeout Workshop, GSFC, 31 May-2 June 2006 10

Gamma-Ray BurstsGamma-Ray Bursts

• GRB080125657 – an intriguing burst!

• Theta = 132 deg (i.e. below the LAT horizon)

• 104 photons triggered and passed OBF (but OBF filtered out all but the lowest energy events).

• 70 events had a fit track – but the reconstructed directions were essentially random.

GLAST LAT Project

DC2 Closeout Workshop, GSFC, 31 May-2 June 2006 11

GRB afterglowsGRB afterglows

• Two basic types– ~Power-law decay (soft)

• Broken power-law, gamma=-1.9 and gamma2=-2.7• Ebreak sweeps from 5 GeV down to 1 GeV as the

afterglow ages.– Bright steady, hard component (hard)

• Broken power-law, gamma=-1.1 and gamma2=-2.0, Ebreak=1000.

– Afterglows were generated for 9 GRB using one or both of the above models (but with varying flux and duration normalizations).

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GRB AfterglowsGRB Afterglows

• GRB080101283 – hard; duration = 5 mins• GRB080104514 - soft + hard; duration = 5 hrs, 5 mins• GRB080105885 – hard; duration = 400s• GRB080107334 - soft; duration = 5 hrs• GRB080118175 – soft; duration = 5 hrs• GRB080127553 – soft; duration = 5 hrs• GRB080131904 – hard; duration = 5 mins• GRB080213493 – soft; duration = 5 hrs• GRB080217126 – soft; duration = 5 hrs

• Fluxes were fairly low – these would be hard to find!

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PBH PBH

• A short very hard transient event.

• Flux increases exponentially, spectra gets harder and cutoff moves to higher energies as a function of time.

• This was designated GRB080106074 by Nukri Komin and David Band (from their blind searches)

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EBL ModelEBL Model

• Kneiske High UV

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Extragalactic diffuseExtragalactic diffuse

• Modeled as a power-law with -2.1 spectrum (Sreekumar 1998).• Cillis and Hartman (2005, ApJ, 621, 291) source subtracted

map has average 5.1e-5 cm-2 s-1 sr-2 (>100MeV). The flux normalisation for the DC2 extragalactic diffuse was obtained by subtracting the galactic diffuse and sum of the 997 DC2 blazars below 5e-8 cm-2 s-1 (approx flux detection limit of EGRET).

GLAST LAT Project

DC2 Closeout Workshop, GSFC, 31 May-2 June 2006 16

Residual backgroundResidual background

Energy distribution of residual background events (classA/GoodEvent3)

The excess at large energies (>10 GeV) would have been greatly lessened if we had implemented Bill’s ACD ribbon cuts (c.f. performance plots shown by Bill at the kickoff meeting.

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Accounting of sourcesAccounting of sources

Source class SourceID range

GRB 1000-1131

Afterglows 2000-2009

PBH 3000

Variable AGN 4000-4203

Steady AGN 4204

Galaxy clusters 5000-5003

Molecular clouds

6000

Dark Matter 7000-7002

Galprop diffuse 8000

Extragal diffuse 8001

Galaxies 9000-9004

Moon 10000-10001

OB assoc 11000-11003

Source class SourceID range

3EG unids 12000-12119

Plerions 13000-13006

SNR 14000-14009

Solar flare 15000

XRB 16000-16004

Pulsars 17000-17037

Pulsars (RL-ms) 18000-18016

Pulsars (RQ-ms) 19000-19211

Pulsars (RL) 20000- 20036

Pulsars (RQ) 21000-21102

Pulsars (EGRET) 22000-22005

Sampled Bkg Negative ID

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Delving more deeplyDelving more deeply

• In the DC2 sky there were 1719 discrete, persistent sources, 134 transient sources, 6 diffuse source (4 dark matter components, galactic diffuse and extragalactic diffuse).

• We have collected information about the DC2 sky model on http://www-glast.slac.stanford.edu/software/DataChallenges/DC2/SkyModel/simulated_data.html

• The DC2 data servers which serve root files, will now return data which contains the MC information (see the merittuple documentation for details).

– The MC variable you probably care most about is McSourceId. This tells you which source produced the event.

• The DC2 FT1 fits data have been reprocessed to add an additional variable: MC_SRC_ID (this is the same as McSourceId).

– You can download an all-sky fits file containing this variable from the website above.

– The GSSC data server will be updated sometime next week.

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WebpagesWebpages

RA sorted table of DC2 sources

FT1 data including MC_SRC_ID

Tables of DC2 sources by source class

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WebpagesWebpages

Pulsars

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WebpagesWebpages

Variable blazars

GLAST LAT Project

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WebpagesWebpages

Gamma-ray bursts

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ConclusionsConclusions

• What has been presented in these talks is an overview of the DC2 sky.

• We encourage everyone to visit the website and compare the details of their analysis against the DC2 truth.

• Have fun!