Compton-thick AGN in the NuSTAR Era. IX. A Joint NuSTAR and XMM-Newton Analysis of Four Local AGN

Silver, R.; Torres-Albà, N.; Zhao, X.; Marchesi, S.; Pizzetti, A.; Cox, I.; Ajello, M.; Cusumano, G.; Parola, V. La; Segreto, A.

doi:10.3847/1538-4357/ac9bf8

Cited by 8 publications

(3 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thanks to the coverage at energies above 10 keV, it will be possible to distinguish the CT AGN from the less obscured ones as the CT AGN are separated by the rest of the sources mainly on the HR HET axis/color. Adding multiwavelength information (e.g., redshifts, infrared fluxes, etc) will constrain the column density to even higher precision and accuracy (e.g., Carroll et al, 2021, Carroll et al, 2023Silver et al, 2023) and therefore deliver a robust sample of CT AGN.…”

Section: Obscured Sources In Surveysmentioning

confidence: 99%

“…There are several other ways in which HEX-P will help us constrain CT space densities. One important approach would be to consider the entire population detected by HEX-P and infer the CT fraction with multi-wavelength diagnostics and machine learning algorithms, in particular using infrared colors (Stern et al, 2005;Stern et al, 2012;Mateos et al, 2013;Assef et al, 2015;Carroll et al, 2021, Carroll et al, 2023Silver et al, 2023). Moreover, given the improved PSF of HEX-P compared to NuSTAR, it will be possible to perform stacking analysis (see the results in Hickox, 2024) at the position of non-X-ray detected candidate CT AGN selected from multiwavelength analysis.…”

Section: Predictions On the Compton-thick Fractionmentioning

confidence: 99%

See 1 more Smart Citation

The high energy X-ray probe (HEX-P): bringing the cosmic X-ray background into focus

Civano,

Zhao,

Boorman

et al. 2024

Front. Astron. Space Sci.

View full text Add to dashboard Cite

Since the discovery of the cosmic X-ray background (CXB), astronomers have strived to understand the accreting supermassive black holes (SMBHs) contributing to its peak in the 10–40 keV band. Existing soft X-ray telescopes could study this population up to only 10 keV, and, while NuSTAR (focusing on 3–24 keV) made great progress, it also left significant uncertainties in characterizing the hard X-ray population, crucial for calibrating current population synthesis models. This paper presents an in-depth analysis of simulations of two extragalactic surveys (deep and wide) with the High-Energy X-ray Probe (HEX-P), each observed for 2 Ms. Applying established source detection techniques, we show that HEX-P surveys will reach a flux of ∼10−15 erg s−1 cm−2 in the 10–40 keV band, an order of magnitude fainter than current NuSTAR surveys. With the large sample of new hard X-ray detected sources (∼2000), we showcase HEX-P’s ability to resolve more than 80% of the CXB up to 40 keV into individual sources. The expected precision of HEX-P’s resolved background measurement will allow us to distinguish between population synthesis models of SMBH growth. HEX-P will leverage accurate broadband (0.5–40 keV) spectral analysis and the combination of soft and hard X-ray colors to provide obscuration constraints even for the fainter sources, with the overall objective of measuring the Compton-thick fraction. With unprecedented sensitivity in the 10–40 keV band, HEX-P will explore the hard X-ray emission from AGN to flux limits never reached before, thus expanding the parameter space for serendipitous discoveries. Consequently, it is plausible that new models will be needed to capture the population HEX-P will unveil.

show abstract

Section: Obscured Sources In Surveysmentioning

confidence: 99%

Section: Predictions On the Compton-thick Fractionmentioning

confidence: 99%

The high energy X-ray probe (HEX-P): bringing the cosmic X-ray background into focus

Civano,

Zhao,

Boorman

et al. 2024

Front. Astron. Space Sci.

View full text Add to dashboard Cite

show abstract

“…Perhaps an even better way is to use a physically motivated torus model (e.g., Murphy & Yaqoob 2009;Baloković et al 2018;Buchner et al 2019). Some recent examples include Marchesi et al (2022), Silver et al (2022), Pizzetti et al (2022), Lefkir et al (2023), Kayal et al (2023), andTorres-Albà et al (2023). However, these methods are time consuming when applied to sources with multiple observations, and thus are not practical for a very large sample of blindly selected sources, especially when over half the sources in these samples tend to show no variability (e.g., Markowitz et al 2014;Hernández-García et al 2015;Laha et al 2020).…”

Section: Introductionmentioning

confidence: 99%

A Simple Method for Predicting N _H Variability in Active Galactic Nuclei

Cox,

Torres-Albà,

Marchesi

et al. 2023

ApJ

Self Cite

View full text Add to dashboard Cite

The unified model of active galactic nuclei (AGNs) includes a geometrically thick obscuring medium to explain the differences between type I and type II AGNs as an effect of inclination angle. This medium is often referred to as the torus and is thought to be “clumpy” as the line-of-sight column density, N H, has been observed to vary in time for many sources. We present a method which uses a variation in the hardness ratio to predict whether an AGN has experienced N H variability across different observations. We define two sets of hard and soft bands that are chosen to be sensitive to the energies most affected by changes in N H. We calculate hardness ratios for Chandra and XMM-Newton observations of a sample of 12 sources with multiple observations, and compare the predictions of this method to the N H values obtained from spectral fitting with physically motivated torus models (borus02, MYTorus, and UXCLUMPY). We also provide a calibrated correction factor that allows comparison between Chandra and XMM-Newton observations which is otherwise not possible due to differences in the instrument response functions. The sensitivity of this method can be easily adjusted. As we decrease the sensitivity, we find that the false positive rate becomes small while the true positive rate remains above 0.5. We also test the method on simulated data and show that it remains reliable for observations with as few as 100 counts. Therefore, we conclude that the method proposed in this work is effective in preselecting sources for variability studies.

show abstract

Compton-thick AGN in the NuSTAR Era X: Analysing seven local CT-AGN candidates

Sengupta¹,

Marchesi²,

Vignali³

et al. 2023

A&A

View full text Add to dashboard Cite

Context. We present the broad-band X-ray spectral analysis (0.6–50 keV) of seven Compton-thick active galactic nuclei (CT-AGN; line-of-sight (LOS) column density > 1024 cm−2) candidates selected from the Swift-BAT 100 month catalogue using archival NuSTAR data. Aims. We aim to obtain a complete census of the heavily obscured AGN in the local Universe (z < 0.05). Methods. This work is in continuation of the ongoing research of the Clemson-INAF group to classify CT-AGN candidates at redshift z < 0.05 using physically motivated torus models. Results. Our results confirm that three out of seven targets are bona fide CT-AGN. Adding our results to the previously analysed sources using NuSTAR data, we increase the population of bona fide CT-AGN by ∼9%, bringing the total number to 35 out of 414 AGN. We also performed a comparative study using MYTorus and borus02 on the spectra in our sample, finding that both physical models are strongly consistent in the parameter space of LOS column density and photon index. Furthermore, we also investigate the clumpiness of the torus clouds by separately computing the LOS and average torus column densities in each of the seven sources. Adding our results to all the previous 48 CT-AGN candidates analysed by the Clemson-INAF research team for which NuSTAR observations are available, we find that 78% of the sources are likely to have a clumpy distribution of the obscuring material surrounding the accreting supermassive black hole.

show abstract

Compton-thick AGN in the NuSTAR Era. IX. A Joint NuSTAR and XMM-Newton Analysis of Four Local AGN

Cited by 8 publications

References 45 publications

The high energy X-ray probe (HEX-P): bringing the cosmic X-ray background into focus

The high energy X-ray probe (HEX-P): bringing the cosmic X-ray background into focus

A Simple Method for Predicting N _H Variability in Active Galactic Nuclei

Compton-thick AGN in the NuSTAR Era X: Analysing seven local CT-AGN candidates

Contact Info

Product

Resources

About

Compton-thick AGN in the NuSTAR Era. IX. A Joint NuSTAR and XMM-Newton Analysis of Four Local AGN

Cited by 8 publications

References 45 publications

The high energy X-ray probe (HEX-P): bringing the cosmic X-ray background into focus

The high energy X-ray probe (HEX-P): bringing the cosmic X-ray background into focus

A Simple Method for Predicting N H Variability in Active Galactic Nuclei

Compton-thick AGN in the NuSTAR Era X: Analysing seven local CT-AGN candidates

Contact Info

Product

Resources

About

A Simple Method for Predicting N _H Variability in Active Galactic Nuclei