The sedentary survey of extreme high-energy peaked BL Lacs

Piranomonte, S.; Perri, M.; Giommi, P.; Landt, Hermine; Padovani, P.

doi:10.1051/0004-6361:20077086

Cited by 59 publications

(80 citation statements)

References 34 publications

(86 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…7, in infrared light, the host galaxy dominates the AGN emission. This is consistent with the optical spectrum measured by Piranomonte et al (2007) when evaluating the redshift of the source (see Figs. 2 and A.1 in their paper) and with the fact that the variability amplitude in the B band is significantly larger than that in the R band.…”

Section: Ssc Modelling Of the Sedsupporting

confidence: 90%

“…1RXS J101015.9−311909 belongs to the ROSAT All Sky Survey Bright Source Catalog (RASS/BSC) of soft (0.1−2 keV) X-ray sources (Voges et al 1999), with a flux of 2.9 × 10 −11 erg cm −2 s −1 . It is located at a position of (α J2000 , δ J2000 ) = (10 h 10 m 15.9 s , −31 • 19 09 ) 1 and has a redshift of z = 0.14 (see Piranomonte et al 2007, for both measurements). The source is present in the NRAO VLA Sky Survey (NVSS) catalogue of radio sources at 1.4 GHz (Condon et al 1998), which lists its flux density as 73.5 ± 2.7 mJy.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Discovery of VHEγ-ray emission and multi-wavelength observations of the BL Lacertae object 1RXS J101015.9 − 311909

Abramowski¹,

Acero²,

Aharonian³

et al. 2012

A&A

View full text Add to dashboard Cite

ABSTRACT1RXS J101015.9−311909 is a galaxy located at a redshift of z = 0.14 hosting an active nucleus (called AGN) belonging to the class of bright BL Lac objects. Observations at high (HE, E > 100 MeV) and very high (VHE, E > 100 GeV) energies provide insights into the origin of very energetic particles present in such sources and the radiation processes at work. We report on results from VHE observations performed between 2006 and 2010 with the H.E.S.S. instrument, an array of four imaging atmospheric Cherenkov telescopes. H.E.S.S. data have been analysed with enhanced analysis methods, making the detection of faint sources more significant. VHE emission at a position coincident with 1RXS J101015.9−311909 is detected with H.E.S.S. for the first time. In a total good-quality livetime of about 49 h, we measure 263 excess counts, corresponding to a significance of 7.1 standard deviations. The photon spectrum above 0.2 TeV can be described by a power-law with a photon index of Γ = 3.08 ± 0.42 stat ± 0.20 sys . The integral flux above 0.2 TeV is about 0.8% of the flux of the Crab nebula and shows no significant variability over the time reported. In addition, public Fermi/LAT data are analysed to search for high energy emission from the source. The Fermi/LAT HE emission in the 100 MeV to 200 GeV energy range is significant at 8.3 standard deviations in the chosen 25-month dataset. UV and X-ray contemporaneous observations with the Swift satellite in May 2007 are also reported, together with optical observations performed with the atom telescope located at the H.E.S.S. site. Swift observations reveal an absorbed X-ray flux of F (0.3−7) keV = 1.04 +0.04 −0.05 × 10 −11 erg cm −2 s −1 in the 0.3−7 keV range. Finally, all the available data are used to study the multi-wavelength properties of the source. The spectral energy distribution (SED) can be reproduced using a simple one-zone Synchrotron Self Compton (SSC) model with emission from a region with a Doppler factor of 30 and a magnetic field between 0.025 and 0.16 G. These parameters are similar to those obtained for other sources of this type.

show abstract

Section: Ssc Modelling Of the Sedsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Discovery of VHEγ-ray emission and multi-wavelength observations of the BL Lacertae object 1RXS J101015.9 − 311909

Abramowski¹,

Acero²,

Aharonian³

et al. 2012

A&A

View full text Add to dashboard Cite

show abstract

“…Studies performed by Massaro et al (2011b) andD'Abrusco et al (2012), based on data from the Wide-field Infrared Survey Explorer (WISE, Wright et al 2010), have shown that blazars tend to concentrate in a distinct region of the IR colour-colour diagram, known as the WISE blazar strip. For this purpose, we used the latest version of the WISE catalogue (ALLWISE), including 747 million objects, and the complete sample of about 150 HSPs from the Sedentary Survey (Giommi et al 1999;Piranomonte et al 2007), which represents well, both in terms of overall SED shape and fluxes, the type of extreme blazars that we want to select in this paper. The Sedentary Survey selects high Galactic latitude (|b| > 20 • ) sources characterised by a very high X-ray to radio flux ratio ( f x / f r ≥ 3 × 10 −10 erg cm −2 s −1 Jy −1 ) by means of a multifrequency method.…”

Section: Building a Large Sample Of Hsp Blazarsmentioning

confidence: 99%

“…Giommi et al 2012a). Following the work of Landt et al (2002) and Piranomonte et al (2007), we assume a giant elliptical host galaxy to be present in every blazar that would leave no imprint on the optical band if the total observed flux f obs exceeds the galaxy flux f ell by at least a factor of 10. Therefore, a lack of redshift allows us to set a lower limit based on the apparent magnitude m in the optical band.…”

Section: Lower Limits On Redshiftsmentioning

confidence: 99%

1WHSP: An IR-based sample of ~1000 VHEγ-ray blazar candidates

Arsioli

Fraga

Giommi

et al. 2015

A&A

Self Cite

103

View full text Add to dashboard Cite

Context. Blazars are the dominant type of extragalactic sources at microwave and at γ-ray energies. In the most energetic part of the electromagnetic spectrum (E > ∼ 100 GeV) a high fraction of high Galactic latitude sources are blazars of the high synchrotron peaked (HSP) type, that is BL Lac objects with synchrotron power peaking in the UV or in the X-ray band. Building new large samples of HSP blazars is key to understand the properties of jets under extreme conditions, and to study the demographics and the peculiar cosmological evolution of these sources. Aims. High synchrotron peaked blazars are remarkably rare, with only a few hundreds of them expected to be above the sensitivity limits of currently available surveys, some of which include hundreds of millions of sources. To find these very uncommon objects, we have devised a method that combines ALLWISE survey data with multi-frequency selection criteria. Methods. The sample was defined starting from a primary list of infrared colour-colour selected sources from the ALLWISE all sky survey database, and applying further restrictions on IR-radio and IR-X-ray flux ratios. Using a polynomial fit to the multi-frequency data (radio to X-ray), we estimated synchrotron peak frequencies and fluxes of each object. Results. We assembled a sample including 992 sources, which is currently the largest existing list of confirmed and candidates HSP blazars. All objects are expected to radiate up to the highest γ-ray photon energies. In fact, 299 of these are confirmed emitters of GeV γ-ray photons (based on Fermi-LAT catalogues), and 36 have already been detected in the TeV band. The majority of sources in the sample are within reach of the upcoming Cherenkov Telescope Array (CTA), and many may be detectable even by the current generation of Cherenkov telescopes during flaring episodes. The sample includes 425 previously known blazars, 151 new identifications, and 416 HSP candidates (mostly faint sources) for which no optical spectra is available yet. The full 1WHSP catalogue is online at http://www.asdc.asi.it/1whsp/, providing a direct link to the SED building tool where multi-frequency data for each source can be easily visualised.

show abstract

“…Following attempts (Wei et al 1999;Bauer et al 2000;Caccianiga et al 2002;Piranomonte et al 2007) have all failed to detect any spectral features and the redshift remains unknown. Piranomonte et al (2007) derived a lower limit z > 0.193 based on the absence of host galaxy features in the spectrum. In the only imaging attempt so far, Nilsson et al (2003) did not detect the host galaxy in a 1200 s R-band exposure.…”

Section: Introductionmentioning

confidence: 99%

Redshift constraints for RGB 0136+391 and PKS 0735+178 from deep optical imaging

Nilsson

Pursimo

Villforth

et al. 2012

A&A

View full text Add to dashboard Cite

We present the results of deep I-band imaging of two BL Lacerate objects, RGB 0136+391 and PKS 0735+178, during an epoch when the optical nucleus was in a faint state in both targets. In PKS 0735+178 we find a significant excess over a point source, which, if fitted by the de Vaucouleurs model, corresponds to a galaxy with I = 18.64 ± 0.11 and r eff = 1.8 ± 0.4 arcsec. Interpreting this galaxy as the host galaxy of PKS 0735+178 we derive z = 0.45 ± 0.06 using the host galaxy as a "standard candle". We also discuss the immediate optical environment of PKS 0735+178 and the identity of the MgII absorber at z = 0.424. Despite of the optimally chosen epoch and deep imaging we find the surface brightness profile of RGB 0136+391 to be consistent with a point source. By determining a lower limit for the host galaxy brightness by simulations, we derive z > 0.40 for this target.

show abstract

The sedentary survey of extreme high-energy peaked BL Lacs

Cited by 59 publications

References 34 publications

Discovery of VHEγ-ray emission and multi-wavelength observations of the BL Lacertae object 1RXS J101015.9 − 311909

Discovery of VHEγ-ray emission and multi-wavelength observations of the BL Lacertae object 1RXS J101015.9 − 311909

1WHSP: An IR-based sample of ~1000 VHEγ-ray blazar candidates

Redshift constraints for RGB 0136+391 and PKS 0735+178 from deep optical imaging

Contact Info

Product

Resources

About