Effects of Redshift on the Classifying Criteria of BL Lacertae Objects

Chen, Luo-En; Xie, Gaogang; Ren, Jiangtao; Xie, Zhao-Hua; Zhou, Shaobing; Wu, H.; Mei, Dong-Cheng

doi:10.1088/1009-9271/7/3/03

Cited by 4 publications

(5 citation statements)

References 28 publications

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“…They argued that BL Lac objects can be gravitationally microlensed radio quasars with continuum emission greatly amplified by stars in a foreground galaxy. Padovani (1992) proposed that either microlensing or evolutionary model are not available to unit BL Lacs and FSRQs and he explained some observed differences between BL Lacs and FSRQs with the beaming model, which is also discussed by Xie et al (2001Xie et al ( , 2007, Cao (2002) and Ma et al (2007). Recently, based on the superluminal sources we proposed that the difference in the ratio of the core luminosity to the extended luminosity in the co-moving frame can explain the different behaviors of the emission lines between BL Lacs and FSRQs (Fan et al 2003).…”

Section: Introductionmentioning

confidence: 94%

A Statistical Study of XBLs, RBLs and FSRQs at 1.5 GHz

Zhou

Jiang

et al. 2007

Chin. J. Astron. Astrophys.

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BL Lac objects are similar to the flat spectrum radio quasars in many aspects except regarding the emission lines. In order to study their relationship, we selected 56 BL Lacertae objects (33 X-ray-selected, 23 radio-selected) and 45 flat spectrum radio quasars, analyzed their radio luminosities and core-dominance parameters. We found that the radio luminosities of the radio selected BL Lac objects located in between the X-ray selected BL Lac objects and the flat spectrum radio quasars. However, this intermediate position does not hold for the core-dominance parameter: the RBLs have the largest core-dominance parameters. This suggests that the core-dominance parameter can not be taken as a sequencing criterion. We also investigated the correlation between the luminosity and the core-dominance parameter for the three subclasses. We concluded that, here, the sequence XBL-RBL-FSRQ still exists.

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Section: Introductionmentioning

confidence: 94%

A Statistical Study of XBLs, RBLs and FSRQs at 1.5 GHz

Zhou

Jiang

et al. 2007

Chin. J. Astron. Astrophys.

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“…As discussed in Section 1, BL Lac objects can be divided into HBLs and LBLs, based on the radio-X-ray spectral index α rx between 5 GHz and 1 keV. According to the literature (Giommi et al 1995;Ma et al 2007;Mei et al 2002;Plotkin et al 2008;Urry & Padovani 1995), most BL Lac objects with α rx ≤ 0.75 are HBLs, and most BL Lac objects with α rx > 0.75 are LBLs. Therefore, to investigate the relations among different blazar subclasses, we adopt α rx = 0.75 as a rough value to separate HBLs from LBLs when applied to SDSS BL Lac objects (Giommi et al 1995;Ma et al 2007;Mei et al 2002;Urry & Padovani 1995).…”

Section: The Sample Of Sdss Blazarsmentioning

confidence: 99%

“…Based on the peak energy frequency of the synchrotron emission peak, BL Lac objects can be divided into "high energy peaked BL Lacs" (HBLs) and "low energy peaked BL Lacs" (LBLs) (Padovani & Giommi 1995;Giommi et al 1995). Mei et al (2002) and Ma et al (2007) found that the two subclasses of BL Lac objects can be distinguished by their peak frequencies ν peak : HBLs have log ν peak > 14.7, while LBLs have log ν peak < 14.7.…”

Section: Introductionmentioning

confidence: 99%

“…The criterion is f x /f r ∼ 10 −11 , corresponding to the broadband spectral index (from 5 GHz in radio to 1 keV in X-ray) α rx ≃ 0.75. HBLs have a broadband spectral index of α rx ≤ 0.75, and LBLs have a spectral index of α rx > 0.75 (Giommi et al 1995;Ma et al 2007;Mei et al 2002;Urry & Padovani 1995). The SEDs of these two different subclasses of BL Lac objects have been investigated by a number of authors (e.g., Bao et al 2008;Chen et al 2006;Padovani & Giommi 1995;Giommi et al 1990;Nieppola et al 2006).…”

Section: Introductionmentioning

confidence: 99%

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The broadband spectral energy distributions of SDSS blazars

Chen

Jiang

et al. 2015

Res. Astron. Astrophys.

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We compiled the radio, optical, and X-ray data of blazars from the Sloan Digital Sky Survey (SDSS) database, and presented the distribution of luminosities and broad band spectral indices. The distribution of luminosities shows that the averaged luminosity of flat-spectral radio quasars (FSRQs) is larger than that of BL Lacs objects. On the other hand, the broad band spectral energy distribution reveals that FSRQs and low energy peaked BL Lac objects (LBLs) objects have similar spectral properties, but high energy peaked BL Lac objects (HBLs) have a distinct spectral property. This may be due to that different subclasses of blazars have different intrinsic environments and are at different cooling levels. Even so, a unified scheme also is revealed from the color-color diagram, which hints that there are similar physical processes operating in all objects under a range of intrinsic physical conditions or beaming parameter.

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“…The first calculation of the energy release by such conversion was proposed by Alcock et al [3] and Olinto [4]. More detailed similar calculation for the conversion of NS to SS/HS was done by Cheng & Dai [5], Ma & Xie [6] and subsequently by many others [7,8,9,10,11,12,13]. Almost all of them found the energy released to be greater than 10 51 ergs, and connected them with the observed gamma ray bursts (GRB).…”

Section: Introductionmentioning

confidence: 95%

Phase transitions in neutron star and magnetars and their connection with high energetic bursts in astrophysics

Mallick

Sahu

2014

Nuclear Physics A

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The phase transition from normal hadronic matter to quark matter in neutron stars (NS) could give rise to several interesting phenomena. Compact stars can have such exotic states up to their surface (called strange stars (SS)) or they can have quark core surrounded by hadronic matter, known as hybrid stars (HS). As the state of matter of the resultant SS/HS is different from the initial hadronic matter, their masses also differ. Therefore, such conversion leads to huge energy release, sometimes of the order of 10 53 ergs. In the present work we study the qualitative energy released by such conversion. Recent observations reveal huge surface magnetic field in certain stars, termed magnetars. Such huge magnetic fields can modify the equations of state (EOS) of the matter describing the star. Therefore, the mass of magnetars are different from normal NS. The energy released during the conversion process from neutron magnetar (NM) to strange magnetar/hybrid magnetar (SS/HS) is different from normal NS to SS/HS conversion. In this work we calculate the energy release during the phase transition in magnetars. The energy released during NS to SS/HS conversion exceeds the energy released during NM to SM/HM conversion. The energy released during the conversion of NS to SS is always of the order of 10 53 ergs. The amount of energy released during such conversion can only be compared to the energy observed during the gamma ray bursts (GRB). The energy liberated during NM to HM conversion is few times lesser, and is not likely to power GRB at cosmological distances. However, the magnetars are more likely to lose their energy from the magnetic poles and can produce giant flares, which are usually associated with magnetars.

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Effects of Redshift on the Classifying Criteria of BL Lacertae Objects

Cited by 4 publications

References 28 publications

A Statistical Study of XBLs, RBLs and FSRQs at 1.5 GHz

A Statistical Study of XBLs, RBLs and FSRQs at 1.5 GHz

The broadband spectral energy distributions of SDSS blazars

Phase transitions in neutron star and magnetars and their connection with high energetic bursts in astrophysics

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