Microlensing<b>constraints</b>on the size of the gamma-ray emission region in blazar B0218+357

Vovk, Ievgen; Neronov, A.

doi:10.1051/0004-6361/201526918

Cited by 24 publications

(25 citation statements)

References 65 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Enhancement periods with time scales of a few tens of days can be obtained for the peaked distribution of clumps up to a magnification factor of ∼ 5. Moreover, such a scenario operates up to much larger (up to ∼0.1 pc) sizes of the emission region in QSO B0218+357 than for the scenario presented in [4].…”

Section: Discussionmentioning

confidence: 91%

“…The interpretation of the change of the magnification ratio of the two images in terms of microlensing on individual stars in the galaxy excludes such a movement [4]. On the other hand, the change in the magnification factor can also be produced by microlensing on extended structures with masses of hundreds of M .…”

Section: Discussionmentioning

confidence: 94%

“…As this effect is sensitive to small changes in the size and location of the emission region, it can be used to study the morphology of sources at unprecedented distance scales. Recently, microlensing was invoked to explain the time variability displayed in the GeV band by the known gravitationally-lensed blazars PKS1830-211 [2,3] and QSO B0218+357 [4]. These authors interpret the changes in the magnification ratio of the leading and trailing component as microlensing due to individual stars in the lensing galaxy.…”

Section: Introductionmentioning

confidence: 99%

“…In 2012, QSO B0218+357 underwent a high state in gamma rays, with a series of outbursts registered by the Fermi Large Area Telescope (LAT) in the GeV range, allowing [14] to measure the gamma-ray delay of 11.46 ± 0.16 days. Decomposition of the emission into two separated components, delayed by ∼11.5 days, revealed changes in their relative magnification ratio [4].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Gamma-Ray Variability Induced by Microlensing on Intermediate Size Structures in Lensed Blazars

Sitarek

Bednarek

2016

Galaxies

View full text Add to dashboard Cite

Abstract:Changes of the magnification ratio of images in a lensed blazar, caused by microlensing on individual stars, have been proposed as a probe of the size and velocity of the emission region in the lensed source. We study whether similar changes in the magnification ratio can be caused by the microlensing on the intermediate size structures in the lensing galaxy, namely stellar clusters and giant molecular clouds. Our numerical simulations show that changes in the magnification ratio of two images with similar time scales (as seen in QSO B0218+357) can be obtained for relativistically-moving emission regions with sizes up to 0.01 pc in the case of microlensing on clumps in giant molecular clouds.

show abstract

Section: Discussionmentioning

confidence: 91%

Section: Discussionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Gamma-Ray Variability Induced by Microlensing on Intermediate Size Structures in Lensed Blazars

Sitarek

Bednarek

2016

Galaxies

View full text Add to dashboard Cite

show abstract

“…The first one is close to the BH and the γ-ray emission is produced inside the broad-line region (BLR; e.g., Dermer & Schlickeiser 1993;Blandford & Levinson 1995;Ghisellini & Madau 1996;Georganopoulos et al 2001;Fan et al 2006;Bai et al 2009;Tavecchio & Mazin 2009;Isler et al 2013;Hu et al 2015). This argument is supported by constraining the size of the γ-ray emission region through the magnification factor during the γ-ray variability in some gravitationally lensed γ-ray blazars (e.g., Neronov et al 2015;Vovk & Neronov 2016), the short variability timescales (down to several hours; e.g., Tavecchio et al 2010), and the sharp breaks at the GeV band seen in the γ-ray spectra of some FSRQs that may caused by the opacity to pair production (e.g. Poutanen 2011).…”

Section: Introductionmentioning

confidence: 98%

Constraints on the Location of γ-Ray Sample of Blazars with Radio Core-shift Measurements

Yan

et al. 2018

ApJ

View full text Add to dashboard Cite

We model simultaneous or quasi-simultaneous multi-band spectral energy distributions (SEDs) for a sample of 25 blazars that have radio core-shift measurements, where a one-zone leptonic model and Markov chain Monte Carlo technique are adopted. In the SED fitting for 23 low-synchrotron-peaked (LSP) blazars, the seed photons from the broad-line (BLR) and molecular torus are considered respectively in the external Compton process. We find that the SED fitting with the seed photons from the torus are better than those utilizing BLR photons, which suggest that the γ-ray emitting region may be located outside the BLR. Assuming the magnetic field strength in the γ-ray emitting region as constrained from the SED fitting follows the magnetic field distribution as derived from the radio core-shift measurements (i.e.,1 , where R is the distance from the central engine and B 1 pc is the magnetic field strength at 1 pc), we further calculate the location of the γ-ray emitting region, g R , for these blazars. We find that~ǵ  R R R 2 10 10 4 S B L R (R S is the Schwarzschild radius and R BLR is the BLR size), where R BLR is estimated from the broad-line luminosities using the empirical correlations obtained using the reverberation mapping methods.

show abstract

The extragalactic gamma-ray sky in the Fermi era

Massaro

Thompson

Ferrara

2015

Astron Astrophys Rev

View full text Add to dashboard Cite

The Universe is largely transparent to γ -rays in the GeV energy range, making these high-energy photons valuable for exploring energetic processes in the cosmos. After 7 years of operation, the Fermi Gamma-ray Space Telescope has produced a wealth of information about the high-energy sky. This review focuses on extragalactic γ -ray sources: what has been learned about the sources themselves and about how they can be used as cosmological probes. Active galactic nuclei (blazars, radio galaxies, Seyfert galaxies) and star-forming galaxies populate the extragalactic high-energy sky. Fermi observations have demonstrated that these powerful nonthermal sources display substantial diversity in energy spectra and temporal behavior. Coupled with contemporaneous multifrequency observations, the Fermi results are enabling detailed, time-dependent modeling of the energetic particle acceleration and interaction processes that produce the γ -rays, as well as providing indirect measurements of the extragalactic background light and intergalactic magnetic fields. Population studies of the γ -ray source classes compared to the extragalactic γ -ray background place constraints on some models of dark matter. Ongoing searches for the nature of the large number of γ -ray sources without obvious counterparts at other wavelengths remain an important challenge.

show abstract

Microlensingconstraintson the size of the gamma-ray emission region in blazar B0218+357

Cited by 24 publications

References 65 publications

Gamma-Ray Variability Induced by Microlensing on Intermediate Size Structures in Lensed Blazars

Gamma-Ray Variability Induced by Microlensing on Intermediate Size Structures in Lensed Blazars

Constraints on the Location of γ-Ray Sample of Blazars with Radio Core-shift Measurements

The extragalactic gamma-ray sky in the Fermi era

Contact Info

Product

Resources

About