The Multiwavelength Approach The Multiwavelength Approach to Unidentified Gamma-Ray to Unidentified Gamma-Ray

SourcesSourcesMOTIVATION: Gamma-ray sources should be

multiwavelength objects.

X-RAYS: Counterpart searches from observation.

SPECTRUM: Pulsars? Neutron Stars?

PULSATION/ROTATION: Periodicity searching.

0.5-

2 K

eV2-

100

KeV

0.1-

10 M

eV>

100

MeV

Gamma-Ray Pulsars

Additional candidates:

>100 MeV

(Thompson, 2001)

Concept: at some level, gamma-ray sources will have X-ray

counterparts. IF the X-ray counterpart can be found, the better X-ray

position information allows deep searches at longer wavelengths. The approach: using an X-ray image of a gamma-ray

source error box, eliminate most of the X-ray sources from

consideration based on their X-ray, optical, and radio properties. Look for a

nonthermal source with a plausible way to produce gamma rays.

The classic example is Geminga. Bignami, Caraveo, Lamb, and

Halpern started this search in 1983. The final result appeared in

1992 with the detection of pulsations from this isolated neutron star.

Counterpart searches from observation

Which sources could be the next Geminga?

(O. Reimer et al., 2001)

RX J0007.0+7302 (possible counterpart to 3EG J0010+7309)AX J1420.1-6049 (possible counterpart to 3EG J1420-6038/GeV J1417-6100)RX J2020.2+4026 (possible counterpart to 3EG J2020+4017)RX J1836.2+5925 (possible counterpart to 3EG J1835+5918)

Using X-ray source catalogue to find counterparts for INTEGRAL sources

EX: Stephen et al 2005, A&A 432 L49

IBIS/ISGRI first year galactic plane survey has produced a catalogue with 123 hard X-ray sources.To find the remaining 28 objects, they have cross-correlated the ISGRI catalogue with the ROSATAll Sky Survey Bright Source Catalogue (RASSBSC).

123» 53 low mass and 23 high mass X-ray binaries, 5 AGN, pulsars, variables and a dwarf nova

75 ROSAT sources»38 low mass X-ray binaries, 13 high mass X-ray binaries, 4AGN/Clusters, 5 pulsars, 3 Cataclysmic variables and 2 other sources.— Of these sources, 10 are in the list of unidentified objects.

IGR J16320-4751: AX J1631.9-4752

1. IBIS (Imager on Board of Integral Satellite): 15keV-10MeV (FOV:9°x9°), angular resolution 12' 2 planes of detector: lower: CsI array: PICsIT, 3100cm2, 200keV-10MeV front: CdTe array, ISGRI, 2600cm2, 15keV-400keV

2. SPI (Spectrometer on Integral): 20keV-8MeV (FOV:16°x16°), angular resolution 2°

The software to analyze the INTEGRAL data

INTEGRAL Off-line Scientific Analysis (OSA): OSA is composed of the following packages:• Off-line Scientific Analysis Software (OSA_SW): 1GBytes

• Instrument Characteristics (OSA_IC): 215 MBytes for IBIS, 540 MBytes for JEMX, 340 MBytes for OMC and 1.4 GBytes for SPI

• 'High-energy' Catalogue (OSA_CAT): 62 Mbytes

• Test Observations, which consist of a set of data and related scripts (OSA_TESTDATA) **A total disk space of 3 GBytes is needed to install all available test data packages. After running the testing scripts, the disk space required grows to 5 Gbytes.

Data Repositories

On 18 Oct. 2004, all public INTEGRAL data become available both in theolder and in the revised format of the Archive.

Data RepositoriesAux: contains auxiliary data products received or created by Auxiliary data PreparationCat: contains observational catalogs necessary for data analysisIc: contains data concerning the instrumental calibrations and operational characteristics that are generated offlineIdx: contains ISDC index files used for fast searching of data for selected data productsObs: contains results of Science AnalysisScw: contains the results of processing from the science window pipelines on a pre-science window basis

RRRRPPPPSSSF.000RRRR is the revolution numberPPPP is the ISOC pointing numberSSS is a sequence used to subdivide pointings or slews during process if requiredF is a flag representing the science window type (0=pointing, 1=slew, 2=non-science, values larger than 2 are unidentified)

Data RepositoriesAn INTEGRAL revolution of three days (about 72 hours) results in a telemetryvolume of approximately 2 Gb. This telemetry stream is processed and analyzedAt the ISDC and will result in about 17 Gb of uncompressed data products perrevolution.

• raw data (4.5 Gb), which are reformatted the same information content as the telemetry sent by the spacecraft.• prepared data (7.2 Gb), including additional timing information• corrected data (2.7 Gb), including gain corrected event energy• high-level products (2.7 Gb), which are the results of the scientific analysis in the form of image, spectra, light curves etc.

How to get INTEGRAL data

http://isdc.unige.ch/index.cgi?Data+browse

Press the 'Save scw list for the creation of Observation Groups' button and Save the file with the name xxxx.list This file will be used later as input forthe og_create program.

Environments of the analysis dataEx: At vela2:export ROOTSYS=/disk2/HEAsoft/osa_sw-5.1/rootexport ISDC_ENV=/disk2/HEAsoft/osa_sw-5.1export ISDC_REF_CAT=$REP_BASE_PROD/cat/hec/gnrl_refr_cat_0023.fits[1]export REP_BASE_PROD=the storage directory of your data my_variable=my_value; export my_variable

ln –s /disk2/HEAsoft/osa_sw-5.1/INTEGRAL_packages/ic icln –s /disk2/HEAsoft/osa_sw-5.1/INTEGRAL_packages/idx idxln –s /disk2/HEAsoft/osa_sw-5.1/INTEGRAL_packages/cat cat

Data analysis

The first step in the data analysis is creation of the Observation Group fromthe list of prepared Science Window Groups DOL’s you want to analyze.For example: To create the file of the list—dith.lst scw/0044/004400540010.001/swg.fits[1] scw/0044/004400550010.001/swg.fits[1] scw/0044/004400560010.001/swg.fits[1] scw/0044/004400570010.001/swg.fits[1]

Then og_create idxSwg=dith.lst ogid=isgri_gc baseDir="./" instrument=IBISCreates a directory obs/isgri_gc with an Observation Group og_ibis.fits in it.

Image Reconstruction I.To start the analysis, move to working directory $REP_BASE_PROD/obs/isgri_gcand call the ibis_science_analysis script

?Light curve

GUI to Do the Scientific Analysisibis_scw1_analysis and ibis_scw2_analysis work on a Science Window basis while ibis_obs1_analysis works on the Observation Group basis.

Process of Scientific Analysis

Composition of the main script ibis_science_analysis.

Background step for Imaging

Background step for Spectra

Background step for Light curves

The General Reference catalog and the Resulted Source listThe objects in the catalog were compiled from the following sources:

• Macomb & Gehrels gamma-ray sources catalog • Liu et al. LMXB and HMXB catalogs • The 4th Uhuru catalog• Van Paradji's X-ray Binaries catalog• HEAO1 A4 catalog• BATSE observations of Piccinotti's sample of AGN• Tartarus reduced AGN data• ASCA Survey catalogs• Recent IAUCs and ATels• INTEGRAL catalogs (archive, survey, GCDE, etc.)• The IGR sources page (J. Rodriguez) In the catalog, you will find information on the name(s) of a source, its position, and error. Identifiers are SIMBAD-compliant and all positions are referenced. Sources in the HTML (http://isdc.unige.ch/Data/cat) version have names that link directly to the relevant page in SIMBAD and a position that links to the reference in ADS. This figure presents the galactic distribution of the latest catalog's 1523 sources. The size and color of

the symbols indicate approximate brightness and hardness, respectively. Symbol size is logarithmically proportional to the total ISGRI+JEM-X counting rates. Hardness is defined as (H−S)/(H+S), where H is the total ISGRI counting rate (20-200 keV), and S is the soft-band (3-10 keV) JEM-X counting rate.

Image Reconstruction II.

Overview of the IMA level products

Image Reconstruction II.

Spectral Extraction

cd $REP_BASE_PROD/obs/isgri_gcfcopy “isgri_srcl_res.fits[ISGR_SRCL_RES][DETSIG >= 6.0]” specat1.fits

Spectral Energy Binning

Input Catalog

Background Map

Number of Energy Bins

Energy Boundaries

Time Resolution

Parameters forLight curve extraction

Results of the Spectral Extraction

Spectra are produced for each science window, Ex:scw/004700530010.001/isgri_spectrum.fits

To achieve a better signal to noise ratio, it can be convenient to sum up spectra of a source from different science windows.

cd $REP_BASE_PROD/obs/isgri_sc

spe_pick group="og_ibis.fits[1]" source="IGR J16320-4751" rootname=IGRJ16320-4751 response=$REP_BASE_PROD/ic/ibis/rsp/\isgr_rmf_grp_0015.fits

As a result two files with spectra of IGR J16320-4751 will be created: IGRJ16320-4751_sum_pha.fits contains the final average spectrum of IGR J16320-4751, while IGRJ16320-4751_single_pha2.fits stores all the original spectra of IGR J16320-4751 that were used to create the average one. In order to deal with the data from different time periods spe_pick was updated and creates now a resulting ARF for your particular dataset. It is written to IGRJ16320-4751_sum_arf.fits and IGRJ16320-4751_single_arf.fits files.

Results of the Spectral ExtractionBefore analyzing the average spectrum with XSPEC:

fparkey 0.02 IGRJ16320-4751_sum_pha.fits SYS_ERR add=yes

Lightcurve ExtractionNote that to extract the lightcurve for a source you need the Pixel Illuminated Fraction (PIF—isgri_pif.fits) map. Such a map is created during the spectral step that we have just run!!

The lightcurve extraction is performed by building shadowgrams for each time and energy bin. Hence this step is time and space consuming. Note that due to CFITSIO limitations, the product of number of energy bins by number of time bins in a science window should be less than 250. ………

Rerunning the analysis |||OrzIn case you want to re-run the analysis with different parameters, run og_create but

this time with a different "ogid" parameter. This will create a new tree under obs/ogid where all the new results will be stored. If the pipeline has crashed, in general it is safer to restart your analysis from scratch removing the obs/ogid directory and restarting from the og_create step!! ………

Because of the group concept you cannot just delete the result you do not like and restart the pipeline. All results that were produced in the course of the analysis are linked to the group, and should be detached before you relaunch the script. To do this you can use the og_clean program, that will clean an Observation Group up to the level specified with parameter endLevel. All data structures with a level equal or prior to endLevel will be kept, while the data structure with a later level will be erased. For example, to run the spectral extraction (SPE level) you should clean from group whatever comes after the BIN_S level, as this is the level immediately preceding the spectral one. og_clean ogDOL="og_ibis.fits[1]" endLevel="BIN_S" If og_clean fails it could be due to the fact that the group was corrupted. You should try to fix it with dal_clean program dal_clean inDOL="og_ibis.fits[1]" checkExt="1" backPtrs="1" checkSum="1" and launch og_clean only afterwards.

Rerunning the analysis |||OrzUnfortunately the current version of og_clean is very slow!!!

In some cases, if you know exactly which data structure has to be detached it would be much faster to launch dal_detach. For example if you run your analysis till SPE, or LCR level, and would like to produce a mosaic image afterwards, you do not have to clean the group, deleting all your results, but just have to detach ISGRI-SRCL-RES data structure (note that with the option "delete=y" all files with this data structure will be deleted): dal_detach og_ibis.fits[1] pattern=ISGR-SRCL-RES delete=y

(Cassam-Chenaї et al. 2004)

The value of L in blackbody model is lower than predicted by standard cooling NS models for which luminosity is ~1034erg s-1 for a NS of a few thousand years (e.g. Tsurata 1998). Such alow luminosity could be explained by accelerated cooling process.Note that the temperature, radius and luminosity of the central point source 1WGA J1713.4-3949 are almost identical to what is found for the central point source in SNR RX J0852.0-4622 (also G266.2-1.2 or "Vela Junior“) adopting a distance of 1 kpc. (Becker & Aschenbach 2002; Kargaltsev et al. 2002)

An Example: 3EG J1835+5918

The spectrum resembles the γ-ray spectraof known γ-ray pulsars like Vela or Geminga (Thompson et al. 1997).

The hard spectral index, as determined to be -1.7 0.06 between 70 MeV and 4GeV.

Compatible with a non-variable source of an average flux of (E >100MeV)7 2 15.9 10 cm s

(O. Reimer et al., 2001)

(Thompson, 2001)

J0218+4252

B1055-52

Geminga

B0656+14

B1509-58

B1046-58

B1706-44

Vela

B1951+32

Crab

T P / 2P

19B 3.2 10 PP

463

PE 4 10

P

38 1/ 2 3/ 2N 1.7 10 P P E

20 3/ 2 1/ 2open 4 10 P P

Characteristic age:

Spin-down energy:

Magnetic field:

Open field line voltage:

The current of relativistic particles flow:

year

erg/s

gauss

volt

s-1

Using X-ray source catalogue to find counterparts for INTEGRAL sources

EX: Stephen et al 2006, A&A Mar.

The second IBIS/ISGRI survey has produced a catalogue with 209 hard X-ray sources.To find the remaining 59 objects, they have cross-correlated the ISGRI catalogue with the ROSATAll Sky Survey Bright Source Catalogue (RASSBSC), ROSAT Faint Source Catalogue and ROSAT HRI catalogue.

Compare with RASSBSC:114 associations - Of these sources, 8 are in the list of unidentified objects.Compare with RFSC:29 correlations - Of these sources, further 9 sources remain unidentified.Compare with ROSAT HRI catalogue:2 unidentified sources are neither in the bright or faint source catalogues.They finally found possible identifications for nine of total 19 objects with X-ray counterparts.