AGN Studies with the LAT

This list is intended to serve as a basis for a written plan for the group activity.

Post-launch activities (1 year and beyond)

 1. Blazar catalog, sample definition

Once the list of GLAST sources is available, three steps are foreseen:

1. A source subset will readily be associated with known sources (e.g. blazars from existig catalogs);
 
2. Some new GLAST sources will be identified via cross-correlation with radio, X-ray... catalogs.
The candidate optical counterparts will be observed. The spectroscopy will confirm their
identity as a blazar, and lead to the redshift and luminosity determination.   

3. Some information about the blazar contents of the remaining subset can be obtained by statistical studies.

Once the sample is correctly defined, the luminosity (logN-logS) and redshift distributions can be established for the different populations.

In addition to BL Lacs and FSRQs, two other AGN populations will be specifically studied:
* radio-galaxies (CenA, M87, PictorA...);  
* radio-quiet galaxies (upper limits will be set in case of no detection).

2. General properties of GLAST-detected blazars

General properties will be studied, as a function of redshit for instance:
* spectral index;
* spectral cutoffs;
* variability, duty cycle.

Standard models like the Synchrotron Self-Compton (SSC) will be used to extract physical parameters using the Spectral Energy Distributions (SED).

3. Extragalactic Background Light

The EBL density will be estimated from the evolution of the SED high-energy cutoffs with redshift.
 
4. Specific Properties of Individual Sources

Several correlations will be studied as a function of time for the flaring blazars:
* Epeak vs Flux;
* Epeak vs Index;
* Index vs Flux.

Multiwavelength campaigns will allow time lags, correlations of fluxes and other parameters for different bands to be measured.

Pre-launch activities

1. "Outreach"

The group is tasked to produce a set of figures illustrating the performance of the LAT in the context of AGN Science.

2. "Demonstration of readiness"

Given the pressure during the first year, it is mandatory that we demonstrate our ability to carry out each of the above studies beforehand. This effort will partly be accomplished during the Data Challenges but complementary work will be needed as well.
This effort will result in the production of technical notes and in publications for studies of general interest (the author list being reduced to the actual contributors).  

3. Modeling - Simulations

A description of the current modeling of AGN for DC2 can be found here.
The simulation tools, as well as the analysis tools must be reviewed/improved/developed as required.
 
Different ingredients are needed:
- luminosity functions;
- EBL estimates;
- "realistic" light curves of flaring blazars;
- etc...

In addition, the capability to compare the observed SEDs with standard model predictions should be developed.

Last updated: 31 May 2005
B. Lott