We use Swift blazar spectra to estimate the key intergalactic medium (IGM) properties of hydrogen column density (NHXIGM), metallicity, and temperature over a redshift range of 0.03 ≤ z ≤ 4.7, using a collisional ionization equilibrium model for the ionized plasma. We adopted a conservative approach to the blazar continuum model given its intrinsic variability and use a range of power-law models. We subjected our results to a number of tests and found that the NHXIGM parameter was robust with respect to individual exposure data and co-added spectra for each source, and between Swift and XMM-Newton source data. We also found no relation between N HXIGM and variations in source flux or intrinsic power laws. Though some objects may have a bulk Comptonization component that could mimic absorption, it did not alter our overall results. The N HXIGM from the combined blazar sample scales as (1 + z)1.8 ± 0.2. The mean hydrogen density at z = 0 is n0 = (3.2 ± 0.5) × 10-7 cm-3. The mean IGM temperature over the full redshift range is log(T/K) =6.1 ± 0.1, and the mean metallicity is [X/H] = -1.62 ± 0.04(Z ∼0.02). When combining with the results with a gamma-ray burst (GRB) sample, we find the results are consistent over an extended redshift range of 0.03 ≤ z ≤ 6.3. Using our model for blazars and GRBs, we conclude that the IGM contributes substantially to the total absorption seen in both blazar and GRB spectra.

Dalton, T., Morris, S., Fumagalli, M., Gatuzz, E. (2021). Probing the physical properties of the intergalactic medium using blazars. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 508(2), 1701-1718 [10.1093/mnras/stab2597].

Probing the physical properties of the intergalactic medium using blazars

Fumagalli M.;
2021

Abstract

We use Swift blazar spectra to estimate the key intergalactic medium (IGM) properties of hydrogen column density (NHXIGM), metallicity, and temperature over a redshift range of 0.03 ≤ z ≤ 4.7, using a collisional ionization equilibrium model for the ionized plasma. We adopted a conservative approach to the blazar continuum model given its intrinsic variability and use a range of power-law models. We subjected our results to a number of tests and found that the NHXIGM parameter was robust with respect to individual exposure data and co-added spectra for each source, and between Swift and XMM-Newton source data. We also found no relation between N HXIGM and variations in source flux or intrinsic power laws. Though some objects may have a bulk Comptonization component that could mimic absorption, it did not alter our overall results. The N HXIGM from the combined blazar sample scales as (1 + z)1.8 ± 0.2. The mean hydrogen density at z = 0 is n0 = (3.2 ± 0.5) × 10-7 cm-3. The mean IGM temperature over the full redshift range is log(T/K) =6.1 ± 0.1, and the mean metallicity is [X/H] = -1.62 ± 0.04(Z ∼0.02). When combining with the results with a gamma-ray burst (GRB) sample, we find the results are consistent over an extended redshift range of 0.03 ≤ z ≤ 6.3. Using our model for blazars and GRBs, we conclude that the IGM contributes substantially to the total absorption seen in both blazar and GRB spectra.
Articolo in rivista - Articolo scientifico
(galaxies:) BL Lacertae objects: general; (galaxies:) intergalactic medium; (stars:) gamma-ray burst: general; galaxies: active; galaxies: high-redshift; X-rays: general;
English
1701
1718
18
Dalton, T., Morris, S., Fumagalli, M., Gatuzz, E. (2021). Probing the physical properties of the intergalactic medium using blazars. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 508(2), 1701-1718 [10.1093/mnras/stab2597].
Dalton, T; Morris, S; Fumagalli, M; Gatuzz, E
File in questo prodotto:
File Dimensione Formato  
stab2597.pdf

Solo gestori archivio

Tipologia di allegato: Publisher’s Version (Version of Record, VoR)
Dimensione 3.26 MB
Formato Adobe PDF
3.26 MB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/367640
Citazioni
  • Scopus 1
  • ???jsp.display-item.citation.isi??? 1
Social impact