M. KALLI Siham

MCA

Directory of teachers

Department

Departement of Physics

Research Interests

Astrophysics - Active galactic nuclei - Super massive black holes - Ultra high energy cosmic rays

Contact Info

University of M'Sila, Algeria

Email : siham.kalli@univ-msila.dz

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Recent Publications

2025-02-01

Mesure de la masse du trou noir au centre de notre Galaxie

Chapitre dans un livre . Titre du livre : Astronomie pour l’éducation dans l’espace Francophone Seconde édition
Titre du chapitre : Mesure de la masse du trou noir au centre de notre Galaxie
ISBN 9782304056495 - Fevrier 2025
Cette activité permet une approche des trois lois de Kepler
et des lois de la gravité de Newton dans le contexte d’un
trou noir ! Les élèves analysent une série d’images montrant le
mouvement des étoiles gravitant autour d’un trou noir, mais
le trou noir central n’est pas visible… Cependant, à l’aide
des trois lois de Kepler et des lois de la gravité de Newton,
le mouvement d’une de ces étoiles permettra de déduire la
présence et de mesurer la masse du trou noir situé au centre
de notre Galaxie ! Cette activité constitue également une
confirmation de la puissance du modèle établi par Newton.
Citation

M. KALLI Siham, Emanuel Rollinde, , (2025-02-01), "Mesure de la masse du trou noir au centre de notre Galaxie", [national] Astronomie pour l’éducation dans l’espace Francophone Seconde édition , Éditions Le Manuscrit Paris

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2024-12-15

Spectral analysis of Seyfert galaxies

Active Galactic Nuclei (AGN) are highly energetic central regions of galaxies, powered by the accretion of material onto supermassive black holes. X-ray observations are a key tool for studying the complex processes occurring in AGN.

X-rays are produced in the accretion disk when ultraviolet (UV) and optical photons from the disk undergo inverse Compton scattering by thermal electrons in the hot corona. This primary X-ray emission forms a power-law spectrum. Additionally, a reflected X-ray component emerges when these primary X-rays irradiate the cooler accretion disk, resulting in further emission.
Several telescopes are dedicated to observing X-rays. In our research, we use data from both XMM-Newton and NuSTAR to study the spectral and timing properties of Seyfert galaxies. These joint observations offer broad energy coverage, enabling us to investigate features such as the soft X-ray excess below 3 keV, the iron Kα lines in the 6-7 keV range, and the Compton hump around 20-30 keV [1]. Moreover, studying X-ray variability in AGN provides a powerful diagnostic tool for probing their physical properties [2,3].
We analyze recent observations of several variable Seyfert galaxies. By performing spectral analysis using relativistic reflection models, we aim to constrain key astrophysical properties of the corona and the accretion disk surrounding the central supermassive black hole.
Citation

M. KALLI Siham, (2024-12-15), "Spectral analysis of Seyfert galaxies", [international] The First International Congress on Recent Advances in Mathematical, Physical and Chemical Sciences (1st-ICRAMPCS 2024) , Universite Constantine 1

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2024-10-21

X-rays analysis of active galactic nuclei

Seyfert galaxies are a significant category of active galactic nuclei (AGN). These galaxies are distinguished by their bright central regions, which are powered by supermassive black holes accreting material. To study these phenomena, various satellites conduct observations across different wavelengths. For instance, XMM-Newton and NuSTAR are two satellites that provide valuable X-ray observations. We examine the X-ray emissions from bright Narrow Line Seyfert galaxies using these satellites, in order to gain crucial insights into the characteristics and behavior of the supermassive black holes and their surrounding accretion disks. These observations help in understanding the complex processes occurring in the cores of active galaxies.

Keywords: AGN, X-rays, Seyfert galaxies, supermassive black holes
Citation

M. KALLI Siham, (2024-10-21), "X-rays analysis of active galactic nuclei", [national] The 1st National Conference on Theoretical Physics Frontiers , Higher Normal School of Technological Education – Skikda

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2024-08-13

Variability and spectral study of seyfert 1 galaxies using long term X-rays observations

The observed iron lines in active galactic nuclei (AGN) offer a powerful tool to study the surroundings of black holes. We will present analysis of recent long-term X-ray observations from XMM-Newton and NuSTAR to study reverberation time delays between the direct continuum and the reflected component, and present detailed spectral analysis to study the environment of the supermassive black holes.
Citation

M. KALLI Siham, (2024-08-13), "Variability and spectral study of seyfert 1 galaxies using long term X-rays observations", [international] All-inclusive AGN - IAU Symposium 394 - IAU General Assembly 2024 , Cape Town - South Africa

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2024-07-15

SMBH properties from long X-rays observations

Mrk 841 is a Type I Seyfert galaxy located at a redshift of z = 0.0365. It has been observed multiple times by
EXOSAT, ASCA, BeppoSAX, XMM-Newton, and NuSTAR. To study various properties of the accretion disk
and the supermassive black hole of our target, we are using the longest and most recent observations from
XMM-Newton: '0882130401' (12/02/2022 - 132 ks), '0882130301' (10/02/2022 - 132 ks), and '0890640201'
(09/01/2022 - 63 ks).
Mrk 841 is known for its strong soft excess [1]. In all XMM-Newton observations, we notice that the 0.5–10
keV count rate variability is dominated by the soft (<3 keV) X-ray variability. For our observations, the ratio
from fitting a simple power law (Γ = 1.70) with Galactic absorption shows a strong soft excess and a clear
line near 6 keV.
Mrk 841 is also known for its complex and highly variable iron line [2]. When fitting our observations, we find
that the data require a broad line and/or narrow lines for different parts of the observations, and the iron line
varies in width and in flux. We then use relativistic reflection models to understand the iron line behavior and
constrain some astrophysical properties.
Citation

M. KALLI Siham, (2024-07-15), "SMBH properties from long X-rays observations", [international] The Origin and Evolution of Supermassive Black Holes, Sexten, Italy, 15-19 July 2024 , Sexten, Italy

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2024-05-21

Spectral and timing analysis of NGC 7314

The analysis of X rays observations from the active galactic nuclei is a good tool to study the properties of the supermassive black hole, the physics of the accretion disk and the corona, and to model their geometries. We present a detailed spectral and timing analysis of the Seyfert galaxy NGC 7314, we used all available public XMM-Newton and NuSTAR observations from 2001 to 2016. In order to improve the spectral modeling, we used both relativistic and non relativistic reflection models. We confirmed the presence of narrow and Broad Iron lines and we obtained constraints for other spectral proprieties. For the timing analysis, we first studied the behaviour of the power density spectrum, then we studied the time delays between the direct X rays emission and the reflected emission from the accretion disk, we measure reverberation in at least one observation, but we do not see it in others, suggesting it may be a transient phenomenon.The analysis of X rays observations from the active galactic nuclei is a good tool to study the properties of the supermassive black hole, the physics of the accretion disk and the corona, and to model their geometries. We present a detailed spectral and timing analysis of the Seyfert galaxy NGC 7314, we used all available public XMM-Newton and NuSTAR observations from 2001 to 2016. In order to improve the spectral modeling, we used both relativistic and non relativistic reflection models. We confirmed the presence of narrow and Broad Iron lines and we obtained constraints for other spectral proprieties. For the timing analysis, we first studied the behaviour of the power density spectrum, then we studied the time delays between the direct X rays emission and the reflected emission from the accretion disk, we measure reverberation in at least one observation, but we do not see it in others, suggesting it may be a transient phenomenon.
Citation

M. KALLI Siham, (2024-05-21), "Spectral and timing analysis of NGC 7314", [national] Physica Scripta , IOP Publishing

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2023-11-09

Détection du trou noir SagittariusA*

Détection du trou noir SagittariusA*, Une detection direct étant impossible, on peut par contre observer l'effet du trou noir sur son entourage, ce qui permet d'étudier ses propriètés, dans le cas de SagittariusA* on etudie les orbites des étoiles autour de ce trou noir supermassif, ce qui permet de déduire sa masse.
Citation

M. KALLI Siham, Emmanuel Rollinde, , (2023-11-09), "Détection du trou noir SagittariusA*", [international] Colloque Astronomie pour l’Education dans l’Espace Francophone , Tunis

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2023-10-09

Spectral analysis of X rays observed from Seyfert galaxies

Seyfert 1 (NLS1) galaxies are important type of active galactic nuclei(AGN). Data analysis of combined observations from X rays satellites, like XMM Newton, Nustar..etc. show important characteristics, on a wide energy interval, of accretion disk surrounding the central super massive black hole,  and  the corona emitting primary X-rays.
Citation

M. KALLI Siham, (2023-10-09), "Spectral analysis of X rays observed from Seyfert galaxies", [international] The Arab Conference on Astronomy and Geophysics , Egypte

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2023-05-10

Spectral modeling of NLS1 galaxy

Active Galactic Nuclei (AGN) are compact regions located at the centers of some galaxies
that emit huge amounts of radiation across the electromagnetic spectrum, especially in the
UV, X-ray, and radio wavelengths. Part of this radiation is produced by matter from an
accretion disk falling into the supermassive black hole at the center of the AGN. An important
type of AGN is Seyfert galaxies, which are characterized by strong emission lines in their
spectra, indicating the presence of highly ionized gas clouds in their central regions. Seyfert
narrow-line 1 (SNL1) galaxies are known for their strong soft excess and steep spectral slope.
AGN are observed using X-ray observatories such as XMM-Newton and NuSTAR. X-rays
are produced due to multiple inverse Compton scatterings of optical/UV accretion disk
photons by hot corona electrons. A part of these primary X-rays (continuum) is reflected on
the accretion disk, producing secondary X-rays. Analyzing both primary and secondary X-
rays enables to study the properties of the supermassive black hole, the accretion disk and the
corona.
In this work, we will study some spectral properties of one of the brightest SNL1 galaxies,
Arakelian 564 (Ark 564), which has a redshift of 0.02468, and a cool corona
Citation

M. KALLI Siham, (2023-05-10), "Spectral modeling of NLS1 galaxy", [national] Computational & Applied Physics Symposium , University of Khemis-Miliana, Algeria

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2023

X rays properties in Seyfert galaxies

In this study, we used archived observations from the XMM-Newton telescope to investigate the statistical characteristics of the timing and spectral variability of X-rays. And for a deeper understanding of Seyfert's X-ray emission, we investigated the Lamp-post and Wind reverberation models by analyzing the time delays between direct X-ray emission from the accretion disc and the reflected emission.
Citation

M. KALLI Siham, Aicha Mohadi, , (2023), "X rays properties in Seyfert galaxies", [international] Mearim VI- Sixth Middle-East and Africa Regional IAU Meeting , The National Research Institute of Astronomy and Geophysics (NRIAG), Cairo, Egypt.

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Reflection specral modeling of Ark564

We studied reflection modeling of a seyfert galaxy Ark564
Citation

M. KALLI Siham, (2023), "Reflection specral modeling of Ark564", [international] X-vision 2023 , NWU - South Africa

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2022

Deployment of a programming framework based on microservices and containers with application to the astrophysical domain

Scientific research is becoming increasingly global and has to address challenges that cannot be handled by small groups or individual researchers. Global research initiatives are often facing the lack of cooperative computing frameworks and storage resources. Such frameworks and resources are needed to address scientific problems at large scales. This paper investigates the potential of using container technologies over distributed computing infrastructure in the astrophysics domain. Due to the complexity of astrophysics applications, it is necessary to enable a parallelism pipeline for their execution. Such applications require High-Performance-Computing (HPC) environments to enable easy and reproducible deployment of astrophysics applications across multiple HPC cites “BRANE”. BRANE provides easy and transparent access to end-users, allowing them to define their execution pipeline
Citation

M. KALLI Siham, (2022), "Deployment of a programming framework based on microservices and containers with application to the astrophysical domain", [national] Astronomy and Computing , Elsevier

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2020

Testing the Lamp-post and Wind Reverberation Models with XMM-Newton Observations of NGC 5506

The lamp-post geometry is often used to model X-ray data of accreting black holes. Despite its simple assumptions, it has proven to be powerful in inferring fundamental black hole properties such as the spin. Early results of X-ray reverberations showed support for such a simple picture, though wind reverberation models have also been shown to explain the observed delays. Here, we analyze new and old XMM-Newton observations of the variable Seyfert-1 galaxy NGC 5506 to test these models. The source shows an emission line feature around 6.7 keV that is delayed relative to harder and softer energy bands. The spectral feature can be modeled with either a weakly relativistic disk line or by scattering in distant material. By modeling both the spectral and timing signatures, we find that the reflection fraction needed to explain the lags is larger than that observed in the time-averaged spectrum, ruling out both static …
Citation

M. KALLI Siham, (2020), "Testing the Lamp-post and Wind Reverberation Models with XMM-Newton Observations of NGC 5506", [national] The Astrophysical Journal , IOP Publishing

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2019

Reverberation in a narrow relativistic line Seyfert galaxy

Seyfert galaxy NGC 5506 is an excellent target for X-rays reverberation, since its spectrum shows both narrow and broad components of the Kα Iron line, and its AGN shows strong X-rays variability. Using different XMM-Newton satellite observations, we study the spectrum in the energy band 2-10 keV.
Citation

M. KALLI Siham, (2019), "Reverberation in a narrow relativistic line Seyfert galaxy", [international] Journal of Physics: Conference Series , iop

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