Confirmation of persistent radio jets in the microquasar LS 5039

Abstract

Abstract. We present here new observations conducted with the EVN and MERLIN of the persistent microquasar LS 5039 discovered by Paredes et al. (2000) with the VLBA. The new observations confirm the presence of an asymmetric two-sided jet reaching up to ∼1000 AU on the longest jet arm. The results suggest a bending of the jets with increasing distance from the core and/or precession. The origin and location of the high-energy gamma-ray emission associated with the system is discussed and an estimate of the magnetic field at the base of the jet given. Our results suggest a well collimated radio jet. We also comment on new observing strategies to be used with satellites and forthcoming detectors, since this persistent source appears to be a rather good laboratory to explore the accretion/ejection processes taking place near compact objects.

Vlba Astrometry of Ls 5039 and PSR J1825-1446: Which Source Is Related to SNR G016.8-01.1?

“…The radio emission of LS 5039 is extended on milliarcsecond scales, evidenced by very long baseline interferometry (VLBI) observations. 5,6,7 This is also the case for the other three gamma-ray binaries already observed at VLBI scales: PSR B1259−63, 8 LS I +61 303, 9 and HESS J0632+057.…”

Galactic Variable Sky With Egret and Glast

“…3.4 for an alternative interpretation of the source.) The microquasar identification and association with EGRET source 3EG J1824-1514 were proposed by Paredes et al 21 As Paredes et al 22 point out LS 5039 should be intrinsically variable in high-energy gamma rays owing to the high eccentricity (e = 0.41) of the orbit, which causes the accretion rate onto the compact object and the intensity of the stellar radiation field in its vicinity to vary. Variability at the 4.1 d period of LS 5039 was not seen in the EGRET data for 3EG J1824-1514, although the limited coverage and sensitivity of the EGRET observations of this source are not particularly constraining and periodic variations are also superimposed on variability of the jets.…”

Constraining the Pulsar Power in Gamma-Ray Binaries Through Thermal X-Ray Emission

“…The star has a stellar radius of R = 9.3 R , and its wind has a terminal velocity of v ∞ = 2400 km s −1 . The detection of elongated asymmetric emission in high-resolution radio images was interpreted as mildly relativistic ejections from a microquasar jet and prompted its identification with an EGRET HE gamma-ray source 22,23 . However, recent Very Long Baseline Array observations show morphological changes on short timescales that might be consistent with a pulsar binary scenario 24 .…”