Abstract
We are compiling a new list of gamma-ray jetted active galactic nuclei (AGN), starting from the fourth catalog of point sources of the Fermi Large Area Telescope (LAT). Our aim is to prepare a list of jetted AGN with known redshifts and classifications to be used to calibrate jet power. We searched in the available literature for all the published optical spectra and multiwavelength studies useful to characterize the sources. We found new, missed, or even forgotten information leading to a substantial change in the redshift values and classification of many sources. We present here the preliminary results of this analysis and some statistics based on the gamma-ray sources with right ascension within the interval 0h--12h (J2000). Although flat-spectrum radio quasars and BL Lac objects are still the dominant populations, there is a significant increase in the number of other objects, such as misaligned AGN, narrow-line Seyfert 1 galaxies, and Seyfert galaxies. We also introduced two new classes of objects: changing-look AGN and ambiguous sources. About one third of the sources remain unclassified.
Highlights
Why This Work?There are many ways to estimate the power emitted by a relativistic jet, but there are serious problems of consistency among the various methods (e.g., [1])
External Compton is dominant in objects with strong optical emission lines, such as flat-spectrum radio quasars (FSRQs) and narrow-line Seyfert 1 galaxies (NLS1s), while BL Lac Objects— characterized by optical spectra with weak or no emission lines—are powered by the synchrotron self-Compton
The third source: 4FGL J0001.5 + 2113 = TXS 2358 + 209, Simbad has 16 references, while NASA/IPAC Extragalactic Database (NED) has 29. Both databases reported z = 1.106 measured by [8]; searching in the available literature, we found that, some years later, this value was changed to z = 0.439 by the same authors on the basis of a better spectrum [9]
Summary
There are many ways to estimate the power emitted by a relativistic jet, but there are serious problems of consistency among the various methods (e.g., [1]). In 2019, we started a program aimed at calibrating the main methods to estimate the jet power and presented some preliminary results [2]. The classification is important in order to apply the most proper formula to calculate the jet power, which, in turn, depends on the main radiative process driving the gamma-ray emission. The classification is important to understand when the jet emission is significantly contaminated by gamma rays from starburst activity as happens in nearby Seyfert galaxies. Another important problem is to divide between beamed (the jet viewed at small angles) and unbeamed (large viewing angles), to understand how much special relativity can boost the jet power. It is better to have a relatively small, but reliable, sample, rather than a large one with significant uncertainties
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