Intrinsic absorbers in BL Lac objects: The XMM-Newton view

Blustin, A. J.; Page, M. J.; Branduardi‐Raymont, G.

doi:10.1051/0004-6361:20034517

Cited by 27 publications

(35 citation statements)

References 14 publications

(33 reference statements)

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“…The observed flux between 2 -10 keV varied from ∼ 2 to ∼ 5 × 10 −11 ergs cm −2 s −1 among various observations, while the photon index varies slightly around 2. While BBXRT reported an Xray absorption feature at ∼ 0.66 keV (Madejski et al 1992;Sambruna et al 1997), we could not confirm this in our Chandra MEG spectrum, consistent with results from recent XMM-Newton observations (Blustin, Page, & Branduardi-Raymont 2004).…”

Section: Xmm-newton Data Analysissupporting

confidence: 79%

High‐Resolution Spectroscopy of X‐Ray Quasars: Searching for the X‐Ray Absorption from the Warm‐Hot Intergalactic Medium

Fang

Canizares

Marshall

2005

ApJ

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We present a survey of six low to moderate redshift quasars with Chandra and XMM-Newton. The primary goal is to search for the narrow X-ray absorption lines produced by highly ionized metals in the Warm-Hot Intergalactic Medium. All the X-ray spectra can be fitted by a power law with neutral hydrogen absorption method. The residuals that may caused by additional emission mechanisms or calibration uncertainties are taken account by polynomial in order to search for narrow absorption features. No real absorption line is detected at above 3-σ level in all the spectra. We discuss the implications of the lack of absorption lines for our understanding of the baryon content of the universe and metallicity of the intergalactic medium (IGM). We find that the non-detection of X-ray absorption lines indicates that the metal abundance of the IGM should be smaller than ∼ 0.3 solar abundance. We also discuss implications of the non-detection of any local (z ∼ 0) X-ray absorption associated with the ISM, Galactic halo or local group, such as has been seen along several other lines of sight (LOS). By comparing a pair of LOSs we estimate a lower limit on the hydrogen number density for the (z ∼ 0) 3C 273 absorber of n H 4 × 10 −3 cm −3 .

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Section: Xmm-newton Data Analysissupporting

confidence: 79%

High‐Resolution Spectroscopy of X‐Ray Quasars: Searching for the X‐Ray Absorption from the Warm‐Hot Intergalactic Medium

Fang

Canizares

Marshall

2005

ApJ

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“…= 40/25). The integrated energy flux between 2 and 10 keV is F 2−10 keV = (2.3 ± 0.2) × 10 −11 erg cm −2 s −1 , an intermediate intensity state with respect to previous X-ray observations (Blustin et al 2004). A broken power-law model with Galactic absorption yields a relatively smooth spectral break (Γ 1 = 1.7 ± 0.1, Γ 2 = 2.0 ± 0.2, E break = 1.7 +1.0 −0.6 keV).…”

Section: Swift/xrt Data Reductionsupporting

confidence: 43%

“…An F-test shows the addition of an absorption edged is significant at the 69% and 92% level for the power-law and broken-power-law cases, respectively. The presence of such an absorption feature is discussed in a recent paper by Blustin et al (2004). If real, it could be transient, as the analysis of XMM/RGS data by these authors reject the presence of such a feature in their spectra.…”

Section: Swift/xrt Data Reductionmentioning

confidence: 98%

Discovery of VHEγ-rays from the BL Lacertae object PKS 0548–322

Aharonian

Akhperjanian

Anton

et al. 2010

A&A

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Aims. PKS 0548−322 (z = 0.069) is a "high-frequency-peaked" BL Lac object and a candidate very high energy (VHE, E > 100 GeV) γ-ray emitter, due to its high X-ray and radio flux. Observations at the VHE band provide insights into the origin of very energetic particles present in this source and the radiation processes at work. Methods. We report observations made between October 2004 and January 2008 with the HESS array, a four imaging atmospheric-Cherenkov telescopes. Contemporaneous UV and X-ray observations with the Swift satellite in November 2006 are also reported. Results. PKS 0548−322 is detected for the first time in the VHE band with HESS We measure an excess of 216 γ-rays corresponding to a significance of 5.6 standard deviations. The photon spectrum of the source is described by a power-law, with a photon index of Γ = 2.86 ± 0.34 stat ± 0.10 sys . The integral flux above 200 GeV is ∼1.3% of the flux of the Crab Nebula, and is consistent with being constant in time. Contemporaneous Swift/XRT observations reveal an X-ray flux between 2 and 10 keV of F 2−10 keV = (2.3 ± 0.2) × 10 −11 erg cm −2 s −1 , an intermediate intensity state with respect to previous observations. The spectral energy distribution can be reproduced using a simple one-zone synchrotron self Compton model, with parameters similar those observed for other sources of this type.

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“…We note, however, that about 40% (= 12/29) of the Piccinotti AGNs are absent in our catalog. In fact, the X-ray fluxes of these 12 AGNs obtained from pointing observations with ASCA, XMM-Newton, or Swift/XRT in more recent years (Winter et al 2009, Shinozaki et al 2006, Aharonian et al 2005, and Blustin et al 2004) are all lower than the typical limiting sensitivity of the MAXI survey, ≈2×10 −11 ergs cm −2 s −1 in the 4-10 keV band (figure 9, in section 4.4), by assuming a power law photon index of 2. This fact indicates that the list of the brightest X-ray AGNs in the whole sky has significantly changed since ∼30 years ago due to their long-term variability.…”

Section: Identificationmentioning

confidence: 99%

The first MAXI/GSC catalog in the high-Galactic latitude sky

Hiroi¹,

Ueda²,

Isobe³

et al. 2012

AIP Conference Proceedings

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We present the first unbiased source catalog of the Monitor of All-sky X-ray Image (MAXI) mission at high Galactic latitudes (|b| > 10 • ), produced from the first 7-month data (2009 September 1 to 2010 March 31) of the Gas Slit Camera in the 4-10 keV band. We develop an analysis procedure to detect faint sources from the MAXI data, utilizing a maximum likelihood image fitting method, where the image response, background, and detailed observational conditions are taken into account. The catalog consists of 143 X-ray sources above 7 sigma significance level with a limiting sensitivity of ∼ 1.5 × 10 −11 ergs cm −2 s −1 (1.2 mCrab) in the 4-10 keV band. Among them, we identify 38 Galactic/LMC/SMC objects, 48 galaxy clusters, 39 Seyfert galaxies, 12 blazars, and 1 galaxy. Other 4 sources are confused with multiple objects, and one remains unidentified. The log N -log S relation of extragalactic objects is in a good agreement with the HEAO-1 A-2 result, although the list of the brightest AGNs in the entire sky has significantly changed since that in 30 years ago.

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Intrinsic absorbers in BL Lac objects: The XMM-Newton view

Cited by 27 publications

References 14 publications

High‐Resolution Spectroscopy of X‐Ray Quasars: Searching for the X‐Ray Absorption from the Warm‐Hot Intergalactic Medium

High‐Resolution Spectroscopy of X‐Ray Quasars: Searching for the X‐Ray Absorption from the Warm‐Hot Intergalactic Medium

Discovery of VHEγ-rays from the BL Lacertae object PKS 0548–322

The first MAXI/GSC catalog in the high-Galactic latitude sky

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