<i>BVR</i> photometry of comparison stars in selected blazar fields

Raiteri, C. M.; Villata, M.; Lanteri, L.; Cavallone, M.; Sobrito, G.

doi:10.1051/aas:1998420

Cited by 73 publications

(83 citation statements)

References 5 publications

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“…Our B magnitudes for stars 3 and 8 and the V magnitude for star 8 are ∼0.10 mag brighter than found by Raiteri et al (1998). This is opposite the systematic trend revealed in the comparison of the results for the field of PKS 1510Ϫ089.…”

Section: Comparison With Previous Resultscontrasting

confidence: 99%

“…Most noticeable is the ∼0.1 mag difference between our results and those of Raiteri et al (1998) for stars in the field of PKS 1510Ϫ089. This difference is difficult to explain because we observed the stars in the field of 3C 279 on the same nights as those of PKS 1510Ϫ089 and there is very close agreement between our results and those of Raiteri et al (1998) for the stars around 3C 279. Also, the BVR magnitudes that Raiteri et al reports for stars 2, 3, and 4 in the field of PKS 0420Ϫ014 are within 0.06 mag of our measurements.…”

Section: Comparison With Previous Resultscontrasting

confidence: 88%

“…This is opposite the systematic trend revealed in the comparison of the results for the field of PKS 1510Ϫ089. Our measurements of star 8 are in much better agreement with those of Angione (1971) and Fiorucci, Tosti, & Rizzi (1998), although Angione's measurement of the B magnitude for star 3 is nearly identical with that of Raiteri et al (1998). There is very good agreement between Angione (1971), Raiteri et al (1998), and us for the magnitude estimates of star 4.…”

Section: Comparison With Previous Resultssupporting

confidence: 70%

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Photometric Calibration of Stars in the Fields of Selected BL Lacertae Objects and Quasars

Smith¹,

Balonek²

1998

PUBL ASTRON SOC PAC

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ABSTRACT. We present the results of UBVRI photometry of stars in the fields of 13 BL Lacertae objects and quasars. The calibrated stars are intended to facilitate photoelectric and CCD differential photometry of these highly variable active galactic nuclei (AGNs). The magnitudes of most of the stars were measured on more than two occasions, and we provide two to five stars per field. Several stars are common to those calibrated by previous observers, although the earlier efforts do not cover all five bandpasses. Our results for these stars are typically in close agreement with previous measurements obtained using common filters. In addition, we present UBVRI magnitudes for stars in the fields of four AGNs (CTA 26, 0716ϩ332, OVϪ236, and PKS 2345Ϫ167) with no previously published comparison stars.

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Section: Comparison With Previous Resultscontrasting

confidence: 99%

Section: Comparison With Previous Resultscontrasting

confidence: 88%

Section: Comparison With Previous Resultssupporting

confidence: 70%

See 1 more Smart Citation

Photometric Calibration of Stars in the Fields of Selected BL Lacertae Objects and Quasars

Smith¹,

Balonek²

1998

PUBL ASTRON SOC PAC

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“…Optical and near-IR data are collected as already calibrated magnitudes, according to a common choice of photometric standards from Raiteri et al (1998). Radio data are provided as calibrated flux densities.…”

Section: Radio-to-optical Observations By the Gaspmentioning

confidence: 99%

AGILE detection of a rapid γ-ray flare from the blazar PKS 1510-089 during the GASP-WEBT monitoring

D’Ammando

Pucella²,

Raiteri

et al. 2009

A&A

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Aims. We report the detection by the AGILE satellite of a rapid γ-ray flare from the source 1AGL J1511−0908, associated with the powerful γ-ray quasar PKS 1510−089, during a pointing centered on the Galactic center region from 1 March to 30 March 2008. This source has been continuosly monitored in the radio-to-optical bands by the GLAST-AGILE Support Program (GASP) of the Whole Earth Blazar Telescope (WEBT). Moreover, the γ-ray flaring episode triggered three ToO observations by the Swi f t satellite in three consecutive days, starting from 20 March 2008. The quasisimultaneous radio-to-optical, UV, X-ray and γ-ray coverage allows us to make a detailed study of the multifrequency time evolution, the spectral energy distribution of this source, and its theoretical interpretation based on the synchrotron and inverse Compton (IC) emission mechanisms. Methods. During the radio-to-optical monitoring provided by the GASP-WEBT, AGILE observed the source with its two co-aligned imagers, the gamma-ray imaging detector (GRID) and the hard X-ray imager (SuperAGILE), which are sensitive in the 30 MeV-30 GeV and 18-60 keV energy bands, respectively. Results. In the period 1-16 March 2008, AGILE detected γ-ray emission from PKS 1510−089 at a significance level of 6.2-σ with an average flux over the entire period of (84 ± 17) × 10 −8 photons cm −2 s −1 for photon energies above 100 MeV. After a predefined satellite re-pointing, between 17 and 21 March 2008, AGILE detected the source at a significance level of 7.3-σ, with an average flux (E > 100 MeV) of (134 ± 29) × 10 −8 photons cm −2 s −1 and a peak level of (281 ± 68) × 10 −8 photons cm −2 s −1 with daily integration. During the observing period January-April 2008, the source also showed an intense and variable optical activity, with several flaring episodes and a significant increase in the flux was observed at millimetric frequencies. Moreover, in the X-ray band, the Swi f t/XRT observations seem to show a harder-when-brighter behavior of the source spectrum. Conclusions. The flat spectrum radio quasar PKS 1510−089 showed strong activity between January and April 2008, with episodes of rapid variability from radio to γ-ray energy bands, in particular with a rapid γ-ray flaring episode. The spectral energy distribution of mid-March 2008 is modeled with a homogeneous one-zone synchrotron self Compton (SSC) emission plus contributions from inverse Compton scattering of external photons from both the accretion disk and the broad line region. Indeed, some features in the optical-UV spectrum seem to indicate Seyfert-like components such as the little and the big blue bumps.

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“…Using differential mode makes the observations insensitive to variations in atmospheric transparency and accurate measurements can be obtained even in partially cloudy conditions. The R-band magnitude of the primary reference star was determined from observations made on photometric nights, using comparison stars in known blazar fields as calibrators (Fiorucci & Tosti 1996;Fiorucci et al 1998;Raiteri et al 1998;Villata et al 1998;Nilsson et al 2007) and taking into account the color term of the R-band filter employed. After the R-band magnitude of the primary reference star was determined, the object magnitudes were computed from the magnitude differences.…”

Section: Optical Datamentioning

confidence: 99%

Planckearly results. XV. Spectral energy distributions and radio continuum spectra of northern extragalactic radio sources

Aatrokoski¹,

Ade²,

Aghanim³

et al. 2011

A&A

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Spectral energy distributions (SEDs) and radio continuum spectra are presented for a northern sample of 104 extragalactic radio sources, based on the Planck Early Release Compact Source Catalogue (ERCSC) and simultaneous multifrequency data. The nine Planck frequencies, from 30 to 857 GHz, are complemented by a set of simultaneous observations ranging from radio to gamma-rays. This is the first extensive frequency coverage in the radio and millimetre domains for an essentially complete sample of extragalactic radio sources, and it shows how the individual shocks, each in their own phase of development, shape the radio spectra as they move in the relativistic jet. The SEDs presented in this paper were fitted with second and third degree polynomials to estimate the frequencies of the synchrotron and inverse Compton (IC) peaks, and the spectral indices of low and high frequency radio data, including the Planck ERCSC data, were calculated. SED modelling methods are discussed, with an emphasis on proper, physical modelling of the synchrotron bump using multiple components. Planck ERCSC data also suggest that the original accelerated electron energy spectrum could be much harder than commonly thought, with power-law index around 1.5 instead of the canonical 2.5. The implications of this are discussed for the acceleration mechanisms effective in blazar shocks. Furthermore in many cases the Planck data indicate that gamma-ray emission must originate in the same shocks that produce the radio emission.

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BVR photometry of comparison stars in selected blazar fields

Cited by 73 publications

References 5 publications

Photometric Calibration of Stars in the Fields of Selected BL Lacertae Objects and Quasars

Photometric Calibration of Stars in the Fields of Selected BL Lacertae Objects and Quasars

AGILE detection of a rapid γ-ray flare from the blazar PKS 1510-089 during the GASP-WEBT monitoring

Planckearly results. XV. Spectral energy distributions and radio continuum spectra of northern extragalactic radio sources

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