1. A Catalog of Candidate High-redshift Blazars for GLAST
TERSI ARIAS
San Francisco State University
Mentor: JENNIFER CARSON
Stanford Linear Accelerator Center
SULI 2006

2. GLAST Gamma-ray Large Area Space Telescope
GLAST Large Area Telescope (LAT)
GLAST is a high-energy gamma-ray observatory
Scheduled to launch in September 2007
Large Area Telescope (LAT)
g-ray detection from 20 MeV – >300 GeV.
Much greater sensitivity with respect to previous instruments.
It is estimated that GLAST will find thousands of new sources.

3. What is a Blazar?
Hubble Space Telescope optical jet image of blazar 3C279
Artist rendition of an AGN
Blazars are a subset of active galactic nuclei (AGN), with relativistic jets oriented at small angles to the line of sight of the observer.
q ~ 1o  blazar

4. Spectral Energy Distribution (SED) of a Blazar
SED Characteristic double peak suggests synchrotron radiation and inverse-Compton scattering
Exponent of power-law in SED interval
F = n -a
a = -log (F2/F1)
Radio Spectral Index of Blazars
Flat spectrum a < 0.5
Spectral Index a
Maraschi et al. 1994
log (n1/n2)
Spectral energy distribution of well studied blazar 3C279.

5. Redshift Distribution of Known Blazars
Low number of high-redshift blazars known
Why are high- redshift blazars interesting?
Solid: All CGRaBS blazars Broken: BL Lacs x 2
From Candidate Gamma-Ray Blazar Survey by Stephen Healey (SLAC)

6. Extragalactic Background Light
Studying the EBL is one motivation for producing a high-redshift blazar catalog

7. Procedures to Find Catalog Candidates
NASA extragalactic database NED
Criteria:
High-redshift z > 2.5
Radio source
Brighter than 70 mJy
How to find a ?:
a=-log (F1/F2)/ log (n1/n2)
a <0.5  blazar !
Finding Fluxes
Surveys:
NRAO/VLA Sky Survey - 1.4GHz band
Catalogs:
Texas – 0.365GHz band
87 Green Bank – 4.85GHz band

8. Results  307 objects for preliminary list of blazars Table
Sample Table
~ 200 objects with flat spectrum
a < 0.5 

9. CONCLUSION Future Work Related
Created a catalog of ~200 high-redshift blazars to be detected by GLAST
Greatly expands the sample of high-redshift blazars
This of blazars can be used to study the EBL
Future Work Related
ApJS paper
Other uses for this catalog (ask Teddy Cheung)

10. Jennifer Carson (my mentor)
ACKNOWLEDGMENTS
Thank you
Jennifer Carson (my mentor)
Teddy Cheung
SLAC-KIPAC
SULI
Students