X–ray Observations of BL Lacertae During 1997 Outburst and its Association with Quasar-like Characteristics

نویسندگان

  • Greg M. Madejski
  • Marek Sikora
  • Tess Jaffe
چکیده

This paper reports on the X–ray emission from BL Lacertae during its July 1997 outburst as observed with the Rossi X–ray Timing Explorer (RXTE), compares the RXTE data to previous measurements, and interprets the overall electromagnetic emission in the context of the currently popular theoretical models. The source is bright and variable, with the 2 – 10 keV flux approximately two to three and a half times higher than measured in November 1995 by Asca. The spectrum is also harder, with power law energy indices of ∼ 0.4− 0.6, compared to ∼ 0.9 in Nov. 1995. Both in the optical band, where BL Lacertae now shows broad emission lines, and in the X–ray band, where the spectrum is hard, the overall electromagnetic distribution of BL Lacertae is similar to that observed in blazars associated with quasars rather than to that seen in the more common High-energy peaked BL Lac type objects (HBLs). We argue that the high energy (X–ray and γ–ray) emission from BL Lacertae consists of two spectral components: X–rays are produced by Comptonization of synchrotron radiation, while the γ–rays produced by Comptonization of the broad emission line flux. Subject headings: X–rays: observations – galaxies: active – quasars: BL Lacertae – theory: radiation mechanisms

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Observations of a Correlated Gamma-Ray and Optical Flare for BL Lacertae

BL Lacertae was detected by the EGRET instrument on CGRO at the 10.2 σ level with an average flux of 171 ± 42 × 10 photons cms at energies > 100 MeV during the optical outburst of 1997 July. This flux is more than 4 times the previously highest level. Within the July 15-22 observation there was a dramatic factor of 2.5 increase in the gamma-ray flux on July 18.75–19.08, apparently preceding by ...

متن کامل

ar X iv : a st ro - p h / 98 06 24 9 v 1 1 8 Ju n 19 98 Analyzing the Multiwavelength Spectrum and Variability of BL Lacertae During the July 1997 Outburst

The multiwavelength spectrum of BL Lacertae during its July 1997 outburst is analyzed in terms of different models for the production of high-energy radiation from blazars. We find that a two-component γ-ray spectrum, consisting of a synchrotron self-Compton and an external Compton component, is required in order to yield an acceptable fit to the broadband spectrum. Our analysis indicates that ...

متن کامل

A Synchrotron Self-Compton Scenario for the Very High Energy γ-ray Emission of the Intermediate BL Lacertae object W Comae

W Comae has significant variability in multi-wavelengthes, from the radio to the gamma-ray bands. A bright outburst in the optical and X-ray bands was observed in 1998, and most recently, a strong TeV flare was detected by VERITAS in 2008. It is the first TeV intermediate-frequency-peaked BL Lacertae (IBL) source. I find that both the broadband spectral energy distributions (SEDs) quasi-simulta...

متن کامل

RXTE Observations of PKS 2155-304 during the November 1997 Gamma-Ray Outburst

We present x-ray observations of the nearby BL Lac PKS 2155-304 taken when it was undergoing a GeV/TeV gamma-ray outburst. During the outburst we measured xray fluxes in the 2-10 keV band that are the largest ever observed for PKS 2155-304. Comparison of these November 1997 measurements and other x-ray observations made contemporaneously with GeV or TeV gamma-ray observations indicate that x-ra...

متن کامل

Optical observations of BL Lacertae from 1997 to 1999

We present the optical (V, R, and I) photometry for BL Lacertae, which was observed from 1997 through 1999, with the 1.56-m telescope at the Shanghai astronomical observatory (SHAO). After the 1997 outburst, it dimmed to a low state and then brightened again. During the period JD 2450701 to JD 2450701.5, variations of 0.40mag, 0.27mag, and 0.21mag over a time scale of 100 minutes were found for...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 1999