LAMP: a micro-satellite based soft x-ray polarimeter for astrophysics

Abstract

The Lightweight Asymmetry and Magnetism Probe (LAMP) is a micro-satellite mission concept dedicated for astronomical X-ray polarimetry and is currently under early phase study. It consists of segmented paraboloidal multilayer mirrors with a collecting area of about 1300 cm 2 to reflect and focus 250 eV X-rays, which will be detected by position sensitive detectors at the focal plane. The primary targets of LAMP include the thermal emission from the surface of pulsars and synchrotron emission produced by relativistic jets in blazars. With the expected sensitivity, it will allow us to detect polarization or place a tight upper limit for about 10 pulsars and 20 blazars. In addition to measuring magnetic structures in these objects, LAMP will also enable us to discover bare quark stars if they exist, whose thermal emission is expected to be zero polarized, while the thermal emission from neutron stars is believed to be highly polarized due to plasma polarization and the quantum electrodynamics (QED) effect. Here we present an overview of the mission concept, its science objectives and simulated observational results.

Systematic study on the quark-hadron mixed phase in compact stars

“…Ever since the first discovery in 1967 [15], more than 2800 pulsars have been observed [16]. This number is increasing exponentially with the implementation of powerful telescopes [17][18][19][20]. Being the natural laboratory of dense matter, the observation of pulsars has put strong constraints on the properties of strongly interacting matter at highest densities [21][22][23][24].…”

Table-top soft x-ray polarimetry setup with rotatable linearly polarized light source

“…4 In China, a microsatellite mission concept called lightweight asymmetry and magnetism probe (LAMP) has been proposed to measure the polarization of monochromatic soft x-rays at ∼250 eV, key technology study is ongoing for this proposal. 5 According to the proposal, the LAMP instrument is planned to be constructed with 16 paraboloidal multilayer mirror sectors mounted circularly around the focal-plane detectors. The multilayer mirrors used in LAMP should provide a sufficiently high reflectivity near the Brewster's angle of 45 deg and simultaneously achieve a high polarization efficiency between s-and p-polarized lights (R s ∕R p ).…”

Vacuum birefringence and the x-ray polarization from black-hole accretion disks

“…In the soft range (1 to 10 keV), the NASA mission IXPE [8] has already been selected in the current SMEX cycle, XIPE is among the 3 ESA M4 candidates [9], and CAS/CNSA mission eXTP is currently in its phase zero [10]. In the sub-keV range, a narrow band (250 eV) polarimeter, LAMP, and a broad band (0.2-0.8 keV) rocketbased polarimeter, REDSox, are currently being designed [11,12]. As for hard x-rays, the balloon-borne X-Calibur [13], with an energy range of 20 to 80 keV, and POGO+ [14], 18 to 160 keV, have already observed the Crab and Cygnus X-1.…”