LOFT: the Large Observatory For X-ray Timing

Abstract

The LOFT mission concept is one of four candidates selected by ESA for the M3 launch opportunity as Medium Size missions of the Cosmic Vision programme. The launch window is currently planned for between 2022 and 2024. LOFT is designed to exploit the diagnostics of rapid X-ray flux and spectral variability that directly probe the motion of matter down to distances very close to black holes and neutron stars, as well as the physical state of ultradense matter. These primary science goals will be addressed by a payload composed of a Large Area Detector (LAD) and a Wide Field Monitor (WFM). The LAD is a collimated (<1 degree field of view) experiment operating in the energy range 2-50 keV, with a 10 m2 peak effective area and an energy resolution of 260 eV at 6 keV. The WFM will operate in the same energy range as the LAD, enabling simultaneous monitoring of a few-steradian wide field of view, with an angular resolution of <5 arcmin. The LAD and WFM experiments will allow us to investigate variability from submillisecond QPO's to yearlong transient outbursts. In this paper we report the current status of the project

A Non-Radial Oscillation Mode in an Accreting Millisecond Pulsar?

“…The largest effective area for fast X-ray timing presently being planned is ESA's LOFT (Feroci et al 2012). The Large Area Detector on LOFT would consist of ≈12 m 2 of silicon detectors and due to the larger collecting area and better (flatter) response above 6-7 keV would provide an increase in source count rate compared to the PCA on RXTE of about a factor of 30 (though the exact scaling would depend on the X-ray spectrum of the source being considered).…”

“…In Section 4 we discuss possible mode identifications for the best candidate frequency in J1751. We also briefly discuss how future observations with larger collecting area missions, such as ESA's Large Observatory for X-Ray Timing (LOFT; Feroci et al 2012) and the Advanced X-Ray Timing Array (Ray et al 2010), can improve the sensitivity of such searches. We conclude with a brief summary of our findings in Section 5.…”

Low-mass neutron stars: universal relations, the nuclear symmetry energy and gravitational radiation

“…A possible way to circumvent this problem is to rely on the fact that all NSs in nature are spinning. Considering rotating NSs is of interest because near-future experiments in the electromagnetic spectrum -such as NICER (Gendreau et al 2012), LOFT (Feroci et al 2012), Astro-H (Takahashi et al 2012) and SKA (Watts et al 2015) -or in the gravitationalwave spectrum -such as Advanced LIGO (Aasi et al 2015), Advanced Virgo (Acernese et al 2015), KAGRA (Somiya 2012) and the Einstein Telescope (Sathyaprakash et al 2012) -could measure or constrain the additional multipoles that determine the structure of rotating NSs or other properties (such as the "Love numbers") that are related to their deformability. Spin-orbit coupling in binary pulsars may allow us to measure the moment of inertia (Damour & Schaefer 1988;Lattimer & Schutz 2005;Bejger et al 2005;Kramer & Wex 2009) and gravitationalwave observations may be used to infer the tidal Love numbers, as well as additional information on the EOS (Mora & Will 2004;Berti et al 2008;Read et al 2009;Hinderer et al 2010;Vines et al 2011;Damour et al 2012;Del Pozzo et al 2013;Favata 2014;Lackey et al 2014;Chatziioannou et al 2015b;Dietrich et al 2015).…”

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].…”