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Presentation  FERMI _HBL presentation.pdf

 

G.Chiaro,  M.Meyer,  M. Di Mauro,  D.Salvetti, G. La Mura,  D.J. Thompson

P R E L I M I N A RY 

Blazars and in particular the subclass of high synchrotron peaked objects are the main targets for the present generation of Imaging Atmospheric Cherenkov Telescopes (IACTs)and will remain of great importance for very high-energy gamma-ray science in light of the future Cherenkov Telescope Array (CTA).

The observation time of high energy sources by IACTs is limited by their small field of view, by the presence of many competing source populations to observe and science cases to study. Therefore, it is important to select the most promising targets in order to save observation time and consequently to increase the number of detections. 

The aim of this study is to search for unclassified blazars , using Artificial Neural Network (ANN) algorithm that can realistically observed with IACTs or CTA in 50 or 5 hours.

The 3FGL catalogue contains two classes of source with uncertain classification that offer opportunities to identify HBLs and subsequently TeV candidates according with the TeV catalog census : (i) the 573 BCU and (ii) 1010 UCSs. Recently in https://arxiv.org/abs/1602.00385 the authors applied a number of machine-learning techniques to classify 3FGL UCSs as pulsars or AGN. The authors found 334 pulsars, 559 sources of AGN type  and 117 remained uncertain.

The resulting 573 BCU and 559 AGN type sources  represent the first targets for this search and we apply an optimized version of the ANN described in https://arxiv.org/abs/1709.05727 in order to compute the likelihood distribution of HBL and non-HBL  sources

We perform an analysis of Fermi-LAT data in order to find the gamma-ray SED of our HBL candidates and confirm the nature of them.
We analyze 104 months of Pass 8 data, from 2008 August 4 to 2017 April 4, selecting gamma-ray events in the energy range E=[0.1,1000] GeV, passing standard data quality selection criteria.

We also compare the extrapolated fluxes of the candidates  against the sensitivity of present IACTs and the future CTA. We use the Fermi-LAT spectral shape of the sources obtained in the range between 0.1 and 300 GeV using the best-fit model parameters from the LAT 4-year 3FGL Catalogue and particularly we referred to the following relation derived from the spectral model that fits the data.

The study is in progress and paper wil come soon.

 

ref.contact  Graziano Chiaro    graziano.chiaro@inaf.it

 

 

 

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Data

3FGL blazar subclasses  HBL and non-HBL distribution against gamma-ray flux

 

 

 

 

 

    Likelihood distribution of HBL and non-HBL  sources in 3FGL blazars by our applied ANN algorithm. 

   This result could show that the applied algorithm is not able to clearly identify HBLs but the likelihood distribution can still be acceptable for the aim of this study

 

Distribution of the ANN likelihood to be HBL candidates of 3FGL BCUs. (right) and UCS_bcu  (left). Vertical blue and steel blue lines indicate the applied classification thresholds  to identify sources as High Confidence candidates.

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Full list of BCU HBL candidates. In Cols. 9, 10, 11 the observabilty at the IACT sites. On the top of the list the candidates with the highest Likelihood  (L> 0.89) .

 

3FGL nameAssociationTSSp.IndexTS_varL_hblRAJ2000DecJ2000HESSVERITASMAGIC
3FGL J0047.9+54471RXS J004754.5+54475856.731.5711.70.9212.01604984.80784405 XX
X 3FGL J1155.4-3417NVSS J115520-341718147.32147.3216.240.92178.8740215-34.32645279X  
 3FGL J1434.6+66401RXS J143442.0+66403173.91.5816.780.92218.722869466.67084133 XX
3FGL J0921.0-2258NVSS J092057-22572162.5162.5110.50.91140.2437951-22.94845947XXX
3FGL J0648.1+16061RXS J064814.1+16070840.11.8113.910.90102.027792916.08911409XXX
 3FGL J1711.6+88461RXS J171643.8+88441444.31.8312.40.90258.670044888.75072331 XX
3FGL J1714.1-20291RXS J171405.2-20274773.81.4418.160.90258.5155102-20.47598092XXX
3FGL J1910.8+28551RXS J191053.2+285622102.251.6115.160.90287.713289928.9403263XXX
 3FGL J0153.4+7114TXS 0149+71080.861.8119.720.8928.4286433571.25516089XX 
 3FGL J0506.9-54351ES 0505-546455.431.4929.820.8976.75704931-54.59583993X

X

 
 3FGL J1944.1-45231RXS J194422.6-452326100.691.6311.110.89296.111321745.38296215X  
           
3FGL J0742.4-8133cSUMSS J074220-81313932.292.0311.80.92115.4463652-81.53829083   
3FGL J0040.3+4049B3 0037+40575.941.9312.020.910.0870837240.83205536   
3FGL J0043.7-11171RXS J004349.3-11161269.41.9112.510.8810.93797337-11.31276512   
3FGL J1824.4+43101RXS J182418.7+43095480.911.8219.740.88276.122822643.17807155   
3FGL J0528.3+18151RXS J052829.6+18165735.691.6714.660.8782.1128930318.27306451   
3FGL J0646.4-5452PMN J0646-5451190.341.4617.370.87101.6181351-54.91863251   
3FGL J1959.8-4725SUMSS J195945-472519923.791.5194.310.87299.9397253-47.42901042   
3FGL J2108.6-86191RXS J210959.5-86185391.041.6510.720.87316.9856579-86.30865936   
3FGL J0039.0-2218PMN J0039-222089.341.6611.610.869.766909807-22.31500028   
3FGL J0305.2-1607PKS 0302-16147.61.622.940.8646.29075836-16.14465396   
3FGL J1040.8+13421RXS J104057.7+13421669.151.711.060.86160.259477313.71799931   
3FGL J2312.9-6923SUMSS J231347-69233235.321.7216.130.86348.4026935-69.39020448   
3FGL J0515.5-0123NVSS J051536-01242745.651.7911.760.8578.87455087-1.419462214   
3FGL J0620.4+2644RX J0620.6+264492.021.5315.10.8595.1734957226.74390304   
3FGL J0640.0-1252TXS 0637-128174.151.5214.440.85100.0137646-12.90013415   
3FGL J0733.5+5153NVSS J073326+515355104.321.6811.180.85113.349175151.86215575   
3FGL J1141.2+68051RXS J114118.3+680433140.091.6823.320.85175.329535768.0822362   
3FGL J1203.5-3925PMN J1203-3926103.21.6918.550.85180.8463393-39.42493679   
3FGL J1939.6-4925SUMSS J193946-49253964.551.8415.920.85294.9560989-49.46611442   
3FGL J2316.8-5209SUMSS J231701-52100337.31.7815.190.85349.2774178-52.18819115   
3FGL J0132.5-0802PKS 0130-08371.921.8712.420.8423.18651181-8.065356912   
3FGL J0342.6-3006PKS 0340-30243.171.9613.370.8455.71024104-30.11480314   
3FGL J1446.8-1831NVSS J144644-18292227.91.78.690.84221.7533056-18.51448366   
3FGL J1855.1-6008PMN J1854-600921.391.836.740.84283.672544-60.1250475   
3FGL J0043.5-04441RXS J004333.7-04425775.941.9111.930.8310.8838869-4.721385702   
3FGL J0746.9+8511NVSS J074715+851208118.951.6718.340.83117.249105985.21791595   
3FGL J0650.5+20551RXS J065033.9+205603206.211.7220.060.82102.638989920.92952844   
3FGL J1319.6+7759NVSS J131921+775823182.641.9525.120.82199.947812978.00731101   
3FGL J1908.8-0130NVSS J190836-012642306.432.135.50.82287.2015241-1.527053471   
3FGL J2347.9+5436NVSS J234753+543627163.041.7821.760.82356.971322754.58170077   
3FGL J0204.2+2420B2 0201+2427.621.712.290.8131.0910223424.27132207   
3FGL J0439.6-31591RXS J043931.4-320045119.861.7424.960.8169.85155048-32.03484089   
3FGL J1547.1-28011RXS J154711.8-28022296.771.7716.750.81236.8077415-28.04443418   
3FGL J1612.4-3100NVSS J161219-305937494.961.86116.180.81243.1006458-30.99149787   
3FGL J0030.2-16461RXS J003019.6-164723168.71.6630.180.87.586848013-16.82218924   
3FGL J1158.9+0818RX J1158.8+081951.451.8111.810.8179.70889418.311328097   
3FGL J1841.2+2910MG3 J184126+2910195.911.7922.890.8280.355824729.15522239   

 

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Full list of BCU HBL candidates. In Cols. 8, 9, 10 the observabilty at the IACT sites. On the top of the list the candidates with the highest Likelihood  (L> 0.89) 

 

3FGL nameTSSp.IndexTS_varL_hblRAJ2000DecJ2000HESSVERITASMAGIC
3FGL J2142.6-2029 36.071.688.190.914325.6572-20.4955XXX
3FGL J2321.6-1619 34.141.7345.130.911350.3966-16.3171XXX
3FGL J2145.5+1007 52.531.7019.900.906326.381510.1296XXX
$3FGL J2300.0+4053 174.531.646.970.904345.058340.8750XXX
          
3FGL J2224.4+0351 29.51.939.550.89336.10203.8590   
3FGL J1525.8-0834 59.521.9223.260.89231.4700-8.5790   
3FGL J1619.1+7538 107.121.8614.910.88244.961075.6730   
3FGL J0251.1-1829 104.261.5810.200.8842.7970-18.4860   
3FGL J0020.9+0323 60.662.0922.500.885.23103.3950   
3FGL J0813.5-0356 57.021.7113.150.88123.3870-3.9390   
3FGL J1234.7-0437 51.542.0029.760.87188.6970-4.6220   
3FGL J1922.2+2313 80.832.2222.630.87290.565023.2260   
3FGL J2043.6+0001 48.482.0124.430.87310.90100.0290   
3FGL J0312.7-2222 177.141.8418.270.8748.1760-22.3710   
3FGL J1513.3-3719 54.741.9118.060.87228.3290-37.3190   
3FGL J0524.5-6937 94.152.0518.370.8681.1280-69.6290   
3FGL J1225.4-3448 22.271.747.010.86186.3560-34.8070   
3FGL J1222.7+7952 43.832.1214.790.86185.996579.8921   
3FGL J2309.0+5428 77.061.7517.680.85347.252054.4760   
3FGL J2015.3-1431 17.421.8114.630.85303.8543-14.5344   
3FGL J2053.9+2922 359.631.7643.970.85313.476029.3740   
3FGL J0234.2-0629 90.72.0020.730.8438.5640-6.1050   
3FGL J1545.0-6641 150.11.5911.850.84236.2650-66.6997   
3FGL J0731.8-3010 37.071.9612.910.84112.9740-30.1770   
3FGL J0952.8+0711 50.961.9114.120.84148.21707.1990   
3FGL J0527.3+6647 51.891.9014.780.8381.900066.7767   
3FGL J1528.1-2904 26.281.8011.720.83232.0360-29.0680   
3FGL J0049.0+4224 36.951.8016.580.8212.253042.4130   
3FGL J1057.6-4051 40.231.7115.540.82164.4090-40.8620   
3FGL J0928.3-5255 98.752.0926.680.8142.0300-52.8680   

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The 3D plot shows the distribution of HBL candidates against  the 3FGL blazar subclasses HBL [blue], IBL [green] , LBL [ red ].

All the candidates lie in the clean HBL  area validating the ANN results that classified the target as HBL sources.

 

 

 

TeV  candidates

We compare the extrapolated fluxes of the candidates against the sensitivity of present IACTs and the future CTA. We used the Fermi-LAT spectral shape of the sources obtained in the range between 0.1 and 300 GeV using the best-fit model parameters from the LAT 4-year 3FGL Catalogue and particularly we referred to the spectral model that fits the data.

We compare the extrapolated fluxes with the CTA sensitivity for 50 hours (5hours) of observations as a solid (dashed) grey line.
Above a declination of 0 degrees we use the sensitivity of the northern array and the southern array otherwise.
The CTA sensitivity for 5 hours of observations is similar to that of currently operating IACTs for 50 hours of observations except a higher threshold energy of ~ 80 GeV. 

 

 

 

 

 

 

 

 

 

 

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