Luigi Foschini

Luigi Foschini
National Institute of Astrophysics | INAF · Astronomical Observatory of Brera

PhD
Relativistic Jets; Active Galactic Nuclei; Foundations of Physics; Physics of Time

About

568
Publications
60,414
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
10,291
Citations
Introduction
Current research fields: Active Galactic Nuclei; Black Holes; Foundations of Physics; High-Energy Astrophysics; Physics of Time; Quantum Gravity; Relativistic Astrophysics; Relativistic Jets; X-ray Binaries.
Additional affiliations
April 2009 - present
National Institute of Astrophysics
Position
  • Researcher
October 2002 - May 2003
University of Geneva
Position
  • Instrument Specialist
Description
  • Detached from INAF/IASF-Bologna at the ISDC Data Centre for Astrophysics as specialist of IBIS/PICsIT onboard the INTEGRAL satellite.
May 2002 - March 2009
National Institute of Astrophysics
Position
  • Researcher
Education
November 1993 - March 1997
University of Bologna
Field of study
  • Physics (Mathematical Physics)
November 1990 - October 1993
University of Bologna
Field of study
  • Electric Engineering (Circuit theory)
November 1983 - February 1990
University of Bologna
Field of study
  • Electric Engineering (Plasma physics and engineering)

Publications

Publications (568)
Book
Full-text available
Late Winter Lecture Notes, Department of Physics and Astronomy, University of Padova.
Preprint
Full-text available
After a short review on the use of time in various branches of physics, I suggest to change the interpretation of time, from a duration to a cut. A reassessment of terminology is also required to avoid meaning traps.
Article
Full-text available
The discovery in 2008 of high-energy gamma-rays from Narrow-Line Seyfert 1 Galaxies (NLS1s) made it clear that there were active galactic nuclei (AGN) other than blazars and radio galaxies that can eject powerful relativistic jets. In addition to NLS1s, the great performance of the Fermi Large Area Telescope made it possible to discover MeV-GeV pho...
Article
Full-text available
We considered the fourth catalog of gamma-ray point sources produced by the Fermi Large Area Telescope (LAT) and selected only jetted active galactic nuclei (AGN) or sources with no specific classification, but with a low-frequency counterpart. Our final list is composed of 2980 gamma-ray point sources. We then searched for optical spectra in all t...
Article
Full-text available
We present the results of a comparison between different methods to estimate the power of relativistic jets from active galactic nuclei (AGN). We selected a sample of 32 objects (21 flat-spectrum radio quasars, 7 BL Lacertae objects, 2 misaligned AGN, and 2 changing-look AGN) from the very large baseline array (VLBA) observations at 43 GHz of the B...
Preprint
Full-text available
The goal of this project is to construct an estimator for the masses of supermassive black holes in active galactic nuclei (AGNs) based on the broad Halpha emission line. We make use of published reverberation mapping data. We remeasure all Halpha time lags from the original data as we find that often the reverberation measurements are improved by...
Article
Full-text available
We present new 1.5–8.5 GHz Very Long Baseline Array (VLBA) observations and 0.32–1.26 GHz Giant Meterwave Radio Telescope (GMRT) observations of J0354−1340, which is the only known radio-quiet (RQ) or radio-intermediate (RI) narrow-line Seyfert 1 galaxy with a 100 kpc, two-sided radio jet. A parsec-scale, one-sided jet in the southeastern direction...
Article
Full-text available
We present the X-ray spectral analysis of two complementary sets of intermediate Seyfert galaxies (ISs). Analyzing X-ray data, we estimate the hydrogen abundance NH and test its connection with the [O III] luminosity acquired from optical observations. The results confirm the conclusions drawn in a previous study concerning the lack of a direct cor...
Article
Full-text available
We present first results of the analysis of optical spectra of two complementary samples of Seyfert galaxies (Seyferts). The first sample was extracted from a selection of the 4th Fermi Gamma-ray Large Area Telescope (4FGL) catalog and consists of 11 γ-ray-emitting jetted Seyfert galaxies. The second one was extracted from the Swift-BAT AGN Spectro...
Article
Full-text available
We report on the first multi-wavelength Swift monitoring campaign performed on SDSS J164100.10+345452.7, a nearby narrow-line Seyfert 1 galaxy that had formerly been considered to be radio-quiet. It has, however, more recently been detected both in the radio (at 37 GHz) and in the γ -ray, a behaviour that hints at the presence of a relativistic jet...
Article
Full-text available
Research in foundations of physics is stagnant, as claimed by many scientists during the last years. I suggest that one reason might be the reification of language, particularly of mathematics, which favour the search for answers to wrong questions. (This is the English translation and revision of an essay published in Italian: L. Foschini, "La r...
Preprint
Full-text available
Research in foundations of physics is stagnant, as claimed by many scientists during the last years. I suggest that one reason might be the reification of language, particularly of mathematics, which favour the search for answers to wrong questions.
Preprint
Full-text available
We considered the fourth catalog of gamma-ray point sources produced by the Fermi Large Area Telescope (LAT) and selected only jetted active galactic nuclei (AGN) or sources with no specific classification, but with a low-frequency counterpart. Our final list is composed of 2980 gamma-ray point sources. We then searched for optical spectra in all t...
Article
Full-text available
La Città del Secondo Rinascimento n. 99, Giugno 2022, p. 13-15
Article
Full-text available
Some highlights of the recent researches in the field of relativistic jets are reviewed and critically analyzed. Given the extent of the available literature, this essay symbolically takes the baton from the outstanding and recent review by Blandford, Meier, and Readhead (2019). Therefore, I focus mostly on the results published during the latest f...
Preprint
Full-text available
Highlights in the field of relativistic jets are reviewed and critically analyzed. Given the extent of the available literature, this essay symbolically takes the baton from the outstanding and recent review by Blandford, Meier, and Readhead (2019). Therefore, I focus mostly on the results published during the latest few years, with specific refere...
Preprint
Full-text available
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...
Article
Full-text available
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...
Article
Full-text available
Narrow-line Seyfert 1 (NLS1) galaxies are a class of active galactic nuclei (AGN) that, in some cases, can harbor powerful relativistic jets. One of them, PKS 2004-447, shows γ -ray emission, and underwent its first recorded multifrequency flare in 2019. However, past studies revealed that in radio this source can be classified as a compact steep-s...
Preprint
Full-text available
Narrow-line Seyfert 1 (NLS1) galaxies are a class of active galactic nuclei (AGN) that, in some cases, can harbor powerful relativistic jets. One of them, PKS 2004-447, shows gamma-ray emission, and underwent its first recorded multifrequency flare in 2019. However, past studies revealed that in radio this source can be classified as a compact stee...
Article
Full-text available
pubblicato su La Città del Secondo Rinascimento, n. 94, Giugno 2021, p. 10-11.
Preprint
Full-text available
The discovery in 2008 of high-energy gamma-rays from Narrow-Line Seyfert 1 Galaxies (NLS1s) made it clear that there were active galactic nuclei (AGN) other than blazars and radio galaxies that can eject powerful relativistic jets. In addition to NLS1s, the great performance of the Fermi Large Area Telescope made it possible to discover MeV-GeV pho...
Article
Full-text available
We present the results of new radio observations carried out with the Karl G. Jan-sky Very Large Array C-configuration at 5.5 GHz for a sample of southern narrow-line Seyfert 1 galaxies (NLS1s). This work increases the number of known radio-detected NLS1s in the southern hemisphere, and confirms that the radio emission of NLS1s is mainly concentrat...
Article
Full-text available
Looking back in time, it is somehow surprising to see the enormous advancement made by astrophysics in just about one century [...]
Preprint
Full-text available
We present the results of new radio observations carried out with the Karl G. Jansky Very Large Array C-configuration at 5.5 GHz for a sample of southern narrow-line Seyfert 1 galaxies (NLS1s). This work increases the number of known radio-detected NLS1s in the southern hemisphere, and confirms that the radio emission of NLS1s is mainly concentrate...
Article
Full-text available
Gamma-ray emitting narrow-line Seyfert 1 (γ-NLS1) galaxies possibly harbour relatively low-mass black holes (106–108 M⊙) accreting close to the Eddington limit, and share many characteristics with their sibling sources, flat-spectrum radio quasars. Although they have been detected in the MeV–GeV band with Fermi–LAT, they have never been seen in the...
Article
Full-text available
Narrow-line Seyfert 1 galaxies (NLSy1s) are a well established class of γ -ray sources, showing the presence of a jet like the more common flat-spectrum radio quasars. The evidence of γ -ray emission poses the issue of the location of the γ -ray emitting zone and of the contribution of the γ - γ absorption within the broad-line region (BLR), since...
Preprint
Full-text available
Gamma-ray emitting narrow-line Seyfert 1 ($\gamma$-NLS1) galaxies possibly harbour relatively low-mass black holes (10$^6$-10$^8$ M$_{\odot}$) accreting close to the Eddington limit, and share many characteristics with their sibling sources, flat-spectrum radio quasars. Although they have been detected in the MeV--GeV band with Fermi-LAT, they have...
Poster
Full-text available
The Narrow-Line Seyfert 1 (NLS1) galaxy SBS 0846+513 is a strong gamma-ray emitter — one of only a handful known. This requires relativistic jets, but NLS1 are nearly all in spiral galaxies, which very rarely produce jets. Furthermore, the smaller black holes of NLS1 had been thought to be unable to produce jets of this scale. But the gamma-ray bri...
Preprint
Full-text available
There are several methods to calculate the radiative and kinetic power of relativistic jets, but their results can differ by one or two orders of magnitude. Therefore, it is necessary to perform a calibration of the jet power, to understand the reasons for these differences (whether wrong hypotheses or intrinsic source variability), and if it is po...
Article
Full-text available
Narrow-line Seyfert 1 galaxies (NLS1s) is one of the few classes of active galactic nuclei harboring powerful relativistic jets and detected in γ -rays. NLS1s are well-known X-ray sources. While in non-jetted sources the origin of this X-ray emission may be a hot corona surrounding the accretion disk, in jetted objects, especially beamed ones, the...
Preprint
Full-text available
Narrow-line Seyfert 1 galaxies (NLS1s) is one of the few classes of active galactic nuclei (AGN) harboring powerful relativistic jets and detected in $\gamma$ rays. NLS1s are well-known X-ray sources. While in non-jetted sources the origin of this X-ray emission may be a hot corona surrounding the accretion disk, in jetted objects, especially beame...
Preprint
Full-text available
We present a detailed study of 11 narrow-line Seyfert 1 galaxies (NLS1s) from the Six-degree Field Galaxy Survey (6dFGS) that both have optical and X-ray spectroscopic observations. There are five complex NLS1s (C-NLS1s) and six simple NLS1s (S-NLS1s). We propose a possible correlation between [O III] line asymmetry and X-ray complexity. The outflo...
Article
Full-text available
Taking advantage of the most recent measurements by means of high-resolution radio observations and other multiwavelength campaigns, it is possible to elaborate a detailed map of the narrow-line Seyfert 1 Galaxy 1H 0323 + 342 . This map will open the possibility of intriguing hypotheses about the generation of high-energy γ rays in the narrow-line...
Preprint
Full-text available
Taking advantage of the most recent measurements by means of high-resolution radio observations and other multiwavelength campaigns, it is possible to elaborate a detailed map of the narrow-line Seyfert 1 Galaxy 1H 0323+342. This map will open the possibility of intriguing hypotheses about the generation of high-energy gamma rays in the narrow-line...
Poster
Full-text available
There are several methods to calculate the radiative and kinetic power of relativistic jets, but their results can differ by one or two orders of magnitude. Therefore, it is necessary to perform a calibration of the jet power, to understand the reasons for these differences (whether wrong hypotheses or intrinsic source variability), and if it is po...
Poster
Full-text available
The location of the gamma-ray emitting region in jetted sources is one of the currently open issues that can be efficiently tackled by future observations with the Cherenkov Telescope Array (CTA). For transients/flaring events (time-scales of ˜1 day or shorter) CTA will be at least two orders of magnitude more sensitive with respect to Fermi-LAT in...
Poster
Full-text available
Time in physics is always viewed from the point of view of duration, but this interpretation causes many problems and paradoxes. I would like to explore a change of interpretation of time. By thinking time as a cut, many problems could be easily solved. Particularly, with such interpretation, quantum gravity theories based on 3+1 spacetime (e.g. Ku...
Preprint
Full-text available
The 1908 June 30 Tunguska Event (TE) is one of the best studied cases of cosmic body impacting the Earth with global effects. However, still today, significant doubts are casted on the different proposed event reconstructions, because of shortage of reliable information and uncertainties of available data. In the present work, we would like to revi...
Presentation
Full-text available
The term "blazar" refers to a cosmic source with a relativistic jet viewed at a small angle, so that the electromagnetic emission is affected by beaming. Historically, blazars are divided into flat-spectrum radio quasars (FSRQs) and BL Lac Objects (BL Lacs). However, the recent discovery that also Seyfert galaxies (particularly Narrow-Line Seyfert...
Preprint
Full-text available
We present a new accurate sample of narrow-line Seyfert 1 galaxies (NLS1s) in the southern hemisphere from the Six-degree Field Galaxy Survey (6dFGS). Based on the optical spectral features, 167 sources were classified as NLS1s. We derived flux-calibrated spectra in the sample for the first time. Strong luminosity correlations between the continuum...
Conference Paper
Full-text available
We present a new accurate sample of narrow-line Seyfert 1 galaxies (NLS1s) in the southern hemisphere from the Six-degree Field Galaxy Survey (6dFGS). Based on the optical spectral features, 167 sources were classified as NLS1s. We derived flux-calibrated spectra in the sample for the first time. Strong luminosity correlations between the continuum...
Article
Full-text available
Gamma-ray emitting narrow-line Seyfert 1 (γ-NLSy1) galaxies are thought to harbour relatively low-mass black holes (10 6-10 8 M ⊙) accreting close to the Eddington limit. They show characteristics similar to those of blazars, such as flux and spectral variability in the gamma-ray energy band and radio properties which point toward the presence of a...
Preprint
Full-text available
Gamma-ray emitting narrow-line Seyfert 1 ($\gamma$-NLSy1) galaxies are thought to harbour relatively low-mass black holes (10$^6$-10$^8$ M$_{\odot}$) accreting close to the Eddington limit. They show characteristics similar to those of blazars, such as flux and spectral variability in the gamma-ray energy band and radio properties which point towar...
Article
e-ASTROGAM (‘enhanced ASTROGAM’) is a breakthrough Observatory space mission, with a detector composed by a Silicon tracker, a calorimeter, and an anticoincidence system, dedicated to the study of the non-thermal Universe in the photon energy range from 0.3 MeV to 3 GeV – the lower energy limit can be pushed to energies as low as 150 keV for the tr...
Article
Full-text available
e-ASTROGAM (‘enhanced ASTROGAM’) is a breakthrough Observatory space mission, with a detector composed by a Silicon tracker, a calorimeter, and an anticoincidence system, dedicated to the study of the non-thermal Universe in the photon energy range from 0.3 MeV to 3 GeV – the lower energy limit can be pushed to energies as low as 150 keV for the tr...
Conference Paper
Full-text available
Gamma-ray emitting narrow-line Seyfert 1 (γ-NLSy1) galaxies are jetted sources hosting a relatively low-mass black hole (10 6-10 8 M ⊙) which accretes close to the Eddington limit. γ-NLSy1 galaxies show flux and spectral variability in the gamma-ray energy band and radio properties similar to those of blazars, which indicate the presence of a relat...
Article
Full-text available
We report simultaneous observations at different energy bands in radio, optical, UV, X-rays and γ rays of the flat-spectrum radio-quasar 3C 345. We built the light curve of the source at different frequencies from 2008, the beginning of the Fermi all-sky survey, to 2016, using new data and public archives. In particular we obtained several optical...
Article
Full-text available
We present a new accurate catalog of narrow-line Seyfert 1 galaxies (NLS1s) in the southern hemisphere from the Six-degree Field Galaxy Survey (6dFGS) final data release, which is currently the most extensive spectroscopic survey available in the southern sky whose database has not yet been systematically explored. We classified 167 sources as NLS1...
Book
Full-text available
Brossura: http://www.bonomoeditore.com/index.php?p=libri&lid=386 // e-Book: http://www.bonomoeditore.com/index.php?p=libri&lid=387
Article
Full-text available
We report the first results of a survey on 74 narrow-line Seyfert 1 galaxies (NLS1s) carried out in 2015 with the Karl J. Jansky Very Large Array (JVLA) at 5 GHz in A-configuration. So far, this is the largest survey aimed to image the radio continuum of NLS1s. We produced radio maps in order to compare the general properties of three different sam...
Presentation
Full-text available
Small asteroids (∼1-100 m size) impacting the Earth’s atmosphere are subject to an explosive fragmentation within a scale height. I review the main theories and the applications to some case studies, such as Tunguska, Sikhote-Alin, Chelyabinsk, and Lugo.
Article
Full-text available
e-ASTROGAM (`enhanced ASTROGAM') is a breakthrough Observatory space mission, with a detector composed by a Silicon tracker, a calorimeter, and an anticoincidence system, dedicated to the study of the non-thermal Universe in the photon energy range from 0.3 MeV to 3 GeV - the lower energy limit can be pushed to energies as low as 150 keV, albeit wi...
Article
Full-text available
We report simultaneous observations at different energy bands in radio, optical, UV, X-rays and $\gamma$ rays of the flat-spectrum radio-quasar 3C 345. We built the light curve of the source at different frequencies from 2008, the beginning of the Fermi all-sky survey, to 2016, using new data and public archives. In particular we obtained several o...
Article
Full-text available
After the discovery of powerful relativistic jets from Narrow-Line Seyfert 1 Galaxies, and the understanding of their similarity with those of blazars, a problem of terminology was born. The word blazar is today associated to BL Lac Objects and Flat-Spectrum Radio Quasars, which are somehow different from Narrow-Line Seyfert 1 Galaxies. Using the s...
Article
Full-text available
In recent years, the old paradigm according to which only high-mass black holes can launch powerful relativistic jets in active galactic nuclei (AGN) has begun to crumble. The discovery of $\gamma$-rays coming from narrow-line Seyfert 1 galaxies (NLS1s), usually considered young and growing AGN harboring a central black hole with mass typically low...
Article
Full-text available
We present the first results of a radio survey of 79 narrow-line Seyfert 1 (NLS1) carried out with the Karl G. Jansky Very Large Array (JVLA) at 5 GHz in A configuration aimed at studying the radio properties of these sources. We report the detection of extended emission in one object: Mrk 783. This is intriguing, since the radio-loudness parameter...
Conference Paper
Full-text available
After the discovery of powerful relativistic jets from Narrow-Line Seyfert 1 Galaxies and the understanding of their similarity with those of blazars, a problem of terminology was born. The word blazar is today associated to BL Lac Objects and Flat-Spectrum Radio Quasars, which are somehow different from Narrow-Line Seyfert 1 Galaxies. Using the sa...
Poster
Full-text available
In recent years, the old paradigm according to which only high-mass black holes can launch powerful relativistic jets in active galactic nuclei (AGN) proved to be incorrect. The discovery of gamma-rays coming from narrow-line Seyfert 1 galaxies (NLS1s), usually considered young and growing AGN harboring a black hole whose mass is typically lower th...
Conference Paper
Full-text available
In recent years, the old paradigm according to which only high-mass black holes can launch powerful relativistic jets in active galactic nuclei (AGN) has begun to crumble. The discovery of γ-rays coming from narrow-line Seyfert 1 galaxies (NLS1s), usually considered young and growing AGN harboring a central black hole with mass typically lower than...
Article
Full-text available
Blazars are the most luminous and variable AGNs, and thus excellent probes of accretion and emission processes close to the central engine. We focus on PKS 1510-089 ($z=0.36$), one of the brightest gamma-ray sources in the Fermi LAT catalog, to study its complex multi-wavelength variability. PKS 1510-089 was observed twice in hard X-rays with the I...
Book
Full-text available
Dispense per le lezioni alla Scuola Estiva 2016 a Saint-Barthélemy (AO) 18-22 Luglio 2016, Lignan (Frazione del Comune di Nus, AO).
Conference Paper
Full-text available
XIPE, the X-ray Imaging Polarimetry Explorer, is a mission dedicated to X-ray Astronomy. At the time of writing XIPE is in a competitive phase A as fourth medium size mission of ESA (M4). It promises to reopen the polarimetry window in high energy Astrophysics after more than 4 decades thanks to a detector that efficiently exploits the photoelectri...
Article
Full-text available
We revisited the spectroscopic characteristics of narrow-line Seyfert 1 galaxies (NLS1s) by analysing a homogeneous sample of 296 NLS1s at redshift between 0.028 and 0.345, extracted from the Sloan Digital Sky Survey (SDSS-DR7) public archive. We confirm that NLS1s are mostly characterized by Balmer lines with Lorentzian profiles, lower black hole...
Poster
Full-text available