Monitoring the Evolution of the X‐Ray Remnant of SN 1987A

Abstract

We report on the results of our monitoring program of the remnant of SN 1987A with the Advanced CCD Imaging Spectrometer (ACIS) on board the Chandra X-ray Observatory. Two new observations have been performed in AO2, bringing the total to four monitoring observations over the past two years. Over this time period, new techniques for correction of "Charge Transfer Inefficiency (CTI)" and for use of charge spreading to provide angular resolution somewhat better than the pixel size of the CCD detector have become available at Penn State. We have processed all four observations using sub-pixel resolution to obtain the highest possible angular resolution, and using our CTI correction software to provide more reliable spectral analysis and flux estimations.The high angular resolution images indicate that the X-ray bright knots are convincingly correlated with the optical spots, primarily at ∼ <1 keV, while higher energy photons are very well correlated with radio images. Our data also provide marginal evidence for radial expansion of the X-ray remnant at a rate of 5200 ± 2100 km s −1 . The X-ray flux appears to linearly increase by ∼60% over the 18 month period of these observations. The spectrum is dominated by broad complexes of atomic emission lines and can be fit with a simple model of a planeparallel shock with electron temperatures of kT ∼ 2 − 4 keV and a postshock electron density of n e ∼ 210 − 420 cm −3 . The implied 0.5 − 10 keV band luminosity in 2001 April is ∼1.3 × 10 35 ergs s −1 ; as of that date, we still observe no direct evidence for the central point source, with an upper limit on the observed luminosity of L X ∼ 5.5 × 10 33 ergs s −1 in the 2 − 10 keV band.

Probing Elemental Abundances in SNR 1987A usingXMM‐Newton

“…Subsequently, Hasinger et al (1996) tracked a steady increase of the soft X-ray flux over 4 yr with ROSAT. Extensive work has since been done by the Chandra Park et al 2002Park et al , 2004Park et al , 2005Park et al [hereafter P05], 2006Park et al , 2007Zhekov et al 2005Zhekov et al , 2006) and XMM-Newton groups (Haberl et al 2006, hereafter H06;Aschenbach 2007, hereafter A07). The general picture gleaned from these studies is of a bimodal plasma distribution present in the region between the forward and reverse shocks (Fig.…”

Supernova remnant 1987A: The latest report from the Chandra X-ray Observatory

“…Utilizing a Monte Carlo simulation (Burrows et al, 2000;Park et al, 2002), we estimate a 90% upper limit on the 3−8 keV band point source counts based on the latest ACIS image of SNR 1987A. We assume a power law spectrum of a photon index Γ = 1.7 for the putative neutron star in order to estimate the X-ray flux corresponding to the Hasinger, Aschenbach, & Trümper (1996).…”

“…Considering its core-collapse, Type II SN origin from a massive progenitor (Sonneborn, Altner, & Kirshner, 1987), as confirmed by the detection of the accompanying neutrino burst (Koshiba et al, 1987), the presence of a compact stellar remnant is predicted for SNR 1987A. There has, however, been no evidence for a pointlike source at the center of the remnant, which has been attributed to optically thick stellar ejecta material surrounding the putative central point source (Burrows et al, 2000;Park et al, 2002Park et al, , 2004. As the blast wave eventually sweeps through the main body of the dense in-ner ring, a dramatic increase of the X-ray flux and morphological/spectral changes of SNR 1987A are expected.…”

The missing compact star of SN1987A: a solid quark star?

“…Shtykovskiy et al (2005) obtained a luminosity limit in the 2-10 keV band of 5 × 10 34 erg s −1 using the XMM-Newton. Park et al (2002Park et al ( , 2004 obtained upper limits of 5.5×10 33 erg s −1 and 1.5 × 10 34 erg s −1 in the same X-ray band using Chandra.…”

“…Yu & Xu (2011) found that the thermal X-ray luminosity has a similar relation with thatĖ, L ∞ bol ∼ 10 −3Ė . Since the observations have given a upper limit of thermal X-ray luminosity L ∞ bol ∼ 10 34 erg s −1 (Park et al 2002(Park et al , 2004, we can get an upper limit of spin energy loss rateĖ. And we can further make a constraint to the parameters of spin and magnetic field of the possible pulsar, becauseĖ is the function of spin and magnetic field,…”