A polarized view of the hot and violent universe

Soffitta, P.; Bucciantini, N.; Churazov, E.; Costa, E.; Dovčiak, Michal; Feng, Hua; Ingram, Adam; Jahoda, K.; Kaaret, Philip; Kallman, Timothy R.; Karas, Vladimír; Khabibullin, Ildar; Krawczynski, H.; Malzac, J.; Marin, Frédéric; Marshall, Herman L.; Matt, Giorgio; Muleri, Fabio; Mundell, C. G.; Pearce, Mark; Petrucci, P. O.; Poutanen, Juri; Romani, Roger W.; Santangelo, A.; Tagliaferri, G.; Taverna, Roberto; Turolla, R.; Vink, Jacco; Zane, S.

doi:10.1007/s10686-021-09722-y

Cited by 11 publications

(11 citation statements)

References 141 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…7e and f, respectively, visually highlights the efficiency of our methods in cleaning up the data from the contamination of the unpolarized emission. Both methods presented here to recover the intrinsic X-ray polarization degree are not limited to IXPE but could also be employed to treat the data coming from future X-ray polarimetry missions such as the enhanced X-ray Timing and Polarimetry mission (eXTP, Zhang et al 2019), the Next Generation X-ray Polarimeter (NGXP, Soffitta et al 2021), or the X-ray Polarization Probe (XPP, Jahoda et al 2019). These missions will have even greater sensitivity and spatial resolution with respect to IXPE.…”

Section: Discussionmentioning

confidence: 99%

Prospects for a polarimetric mapping of the Sgr A molecular cloud complex with IXPE

Ferrazzoli

Gesu

Donnarumma

et al. 2021

A&A

View full text Add to dashboard Cite

Context. The X-ray polarization degree of the molecular clouds surrounding Sgr A* is expected to be greatly reduced due to the mixing of the polarized reflection emission with the unpolarized thermal emission that pervades the Galactic center region. This makes this type of observation a challenging experiment for the upcoming Imaging X-ray Polarimeter Explorer (IXPE), whose launch is expected in 2021. Aims. We aim to determine the detectability of four molecular clouds of the Sgr A complex (MC2, Bridge B2, Bridge E, and G0.11-0.11) in a realistic IXPE pointing of the Sgr A field of view. We assess the minimum increase in the detectable polarization when a molecular cloud is off-axis. We provide two different strategies for reconstructing the intrinsic cloud polarization once the data is available. Methods. We used the Monte Carlo tool ixpeobssim to simulate IXPE observations of the Sgr A molecular cloud complex. We used Chandra maps and spectra to model the diffuse emission in the Galactic center region along with a realistic model of the instrumental and diffuse background. We created synthetic polarization products of the unpolarized emission and combined them with a test data set obtained from a simulation of a 2 Ms long IXPE observation to retrieve the intrinsic polarization degree of the molecular clouds. Results. We find that for the molecular clouds considered here, the minimum detectable polarization (MDP) increases by ~1–15% with respect to the case in which a cloud is observed on-axis. We successfully retrieve the intrinsic polarization degree in the 4.0–8.0 keV band and line-of-sight distance of one of them taken as an example, namely, G0.11-0.11, by correcting the observed (i.e., for a 2 Ms-long simulation) polarization degree map using either a synthetic dilution map or a Stokes intensity map of the unpolarized emission. With both methods, the position of the cloud along the line-of-sight is derived from the reconstructed polarization degree with an uncertainty of 7 and 4 pc, respectively. Conclusions. We confirm the results of previous studies, finding that G0.11-0.11 is the most promising target. For the Sgr A molecular complex region, we propose an observation strategy that may permit detection up to three clouds in the 4.0–8.0 keV band, depending on their true line-of-sight position. We demonstrate that by using simulated data products of the unpolarized components, it is possible to clean up the observed polarization maps from the environmental contamination. The methods we present here are potentially useful for the analysis of X-ray polarimetric data of any extended source that is affected by environmental dilution of the polarized signal. To accurately measure (i.e, with uncertainties of the order of a few parsec) the distance of the cloud along the line-of-sight, a high-quality spectrum and image of the clouds quasi simultaneous to the IXPE pointing are needed.

show abstract

Section: Discussionmentioning

confidence: 99%

Prospects for a polarimetric mapping of the Sgr A molecular cloud complex with IXPE

Ferrazzoli

Gesu

Donnarumma

et al. 2021

A&A

View full text Add to dashboard Cite

show abstract

“…For our tasks, we are mainly interested in the polarisation of thermal surface emissions which passed through the magnetosphere. This topic has been the subject of intensive theoretical studies during the last few years (see, for example, [218] as an example of the first models oriented to near-future X-ray observations), as several specialised X-ray missions have been proposed by main space agencies, and two of them-NASA's IXPE and China's eXTP-have been approved [219]. These satellites will be especially effective in magnetar observations.…”

Section: Polarisationmentioning

confidence: 99%

Evolution of Neutron Star Magnetic Fields

2021

View full text Add to dashboard Cite

Neutron stars are natural physical laboratories allowing us to study a plethora of phenomena in extreme conditions. In particular, these compact objects can have very strong magnetic fields with non-trivial origin and evolution. In many respects, its magnetic field determines the appearance of a neutron star. Thus, understanding the field properties is important for the interpretation of observational data. Complementing this, observations of diverse kinds of neutron stars enable us to probe parameters of electro-dynamical processes at scales unavailable in terrestrial laboratories. In this review, we first briefly describe theoretical models of the formation and evolution of the magnetic field of neutron stars, paying special attention to field decay processes. Then, we present important observational results related to the field properties of different types of compact objects: magnetars, cooling neutron stars, radio pulsars, and sources in binary systems. After that, we discuss which observations can shed light on the obscure characteristics of neutron star magnetic fields and their behaviour. We end the review with a subjective list of open problems.

show abstract

“…This topic is a subject of intensive theoretical studies during the last few years (see e.g. [211] as an example of first models oriented to near-future Xray observations) as several specialised X-ray missions have been proposed by main space agencies, and two of them -NASA's IXPE and China's eXTP -are approved [212]. These satellites will be especially effective in magnetar observations.…”

Section: Polarisationmentioning

confidence: 99%