The Large Observatory for x-ray timing

Abstract

The Large Observatory For x-ray Timing (LOFT) was studied within ESA M3 Cosmic Vision framework and participated in the final downselection for a launch slot in 2022-2024. Thanks to the unprecedented combination of effective area and spectral resolution of its main instrument, LOFT will study the behaviour of matter under extreme conditions, such as the strong gravitational field in the innermost regions of accretion flows close to black holes and neutron stars, and the supranuclear densities in the interior of neutron stars. The science payload is based on a Large Area Detector (LAD, 10 m2 effective area, 2-30 keV, 240 eV spectral resolution, 1° collimated field of view) and a Wide Field Monitor (WFM, 2-50 keV, 4 steradian field of view, 1 arcmin source location accuracy, 300 eV spectral resolution). The WFM is equipped with an on-board system for bright events (e.g. GRB) localization. The trigger time and position of these events are broadcast to the ground within 30 s from discovery. In this paper we present the status of the mission at the end of its Phase A study

Colloquium: Measuring the neutron star equation of state using x-ray timing

“…To exploit them to measure the EOS, however, requires larger area instruments, and various mission concepts are now being proposed. These have included the 3 m 2 Advanced X-ray Timing Array (AXTAR: Ray et al, 2010), and the 8.5-10 m 2 Large Observatory for X-ray Timing, LOFT (Feroci et al, 2012(Feroci et al, , 2014, see also the LOFT ESA M3 Yellow Book http://sci.esa.int/loft/53447-loft-yellow-book).…”

“…In this Section we will explore each technique in turn, and discuss the contraints on the EOS that would be achievable with a large area (∼ 10 m 2 ) hard X-ray (2-30 keV) timing telescope. Much of the work presented here was developed as part of the science case for the proposed Large Observatory for X-ray Timing (LOFT: Feroci et al, 2012Feroci et al, , 2014, and the LOFT ESA M3 Yellow Book, http://sci.esa.int/loft/53447-loft-yellow-book).…”

The enhanced X-ray Timing and Polarimetry mission—eXTP

“…The eXTP mission is an enhanced version of the Chinese X-ray Timing and Polarimetry mission [6], which in 2011 was selected and funded for a Phase 0/A study as one of the background concept missions in the Strategic Priority Space Science Program of the Chinese Academy of Sciences (CAS). Also in 2011, the Large Observatory for Timing (LOFT) mission concept [7,8] was selected for an assessment study in the context of the ESA's Announcement of Opportunity for the third of the medium size missions (M3) foreseen in the framework of the Agency's Cosmic Vision programme. The LOFT study was carried out in 2011-2014 by a consortium of European institutes.…”

Four-hair relations for differentially rotating neutron stars in the weak-field limit

“…Since the NS equation of state (EoS) -the relation between state variables such as pressure and density -is unknown, one must fit all of these parameters to the data independently, thus diluting the information that can be extracted. Reducing the number of independent parameters in an EoS independent way would help extract more information from observables [17,18], and in particular, it may allow for the precise extraction of the NS mass and radius with NICER [19] and LOFT [20][21][22].…”