Post on 04-Aug-2020
Magnetar (J1745-2900) with EAVN
Wu Jiang (江悟), SHAO
in collaborations with EAVN Tiger Team and AGN Science Working Group
2018.09.05
11th EAVN Workshop 2018, 4-7 Sep 2018, PyeongChang, Korea
MotivationsRare ShareCadenceIncrease
Discovery of magnetar J1745-2900
First profile -Swift BAT (X-ray)
Kennea et al. ApJL, 2013
Eatough et al, Nature, 2013
Radio emission of Magnetar J1745-2900
Torne et al, MNRAS, 2015 Torne et al, MNRAS, 2017
Mar, 2015Apr-May, 2013 Jul-Aug, 2014
Radio spectral index of Magnetar J1745-2900
Torne et al, MNRAS, 2015, 2017
Mar, 2015Jul-Aug, 2014
a = -0.4 ± 0.1 a = +0.4 ± 0.2
CHANDAR picture
http://chandra.harvard.edu/photo/2015/sgr1745/
Magnetar-SgrA*
A 2.4" projecteddistance translates ina minimum physicalseparationd = 0.09+/-0.02 pc(90% CL) for D=8.3 kpc
Neighbor to SgrA*Magnetar (Soft Gamma Repeater, SGR)
2.4"
Magnetar J1745-2900 vs. EAVN
2.4"
A 2.4" separation means magnetar-SgrA* shares thein/same beam even for Tianma65 in Q band (22"). Share similar physical conditions with SgrA* Share LP monitoring of SgrA* High frequency astrometry
Kravchenko et al. MNRAS, 2016
VLA, 7mm
Magnetar J1745-2900 vs. EAVN
High frequency (K/Q): Invert spectrum,reduce the scattering effect
Share the same observation with SgrA*,increase the target source but noadditional observation time
Feed back to SgrA* data analysis
RMS (image of SgrA): 0.3 mJy@K, 1 mJy@Q
Magnetar J1745-2900 with VLBA+VLA
Bower et al. ApJL,2014
VLBA, 8.7 GHz VLBA, 15.4 GHz
Proper motion of magnetar J1745-2900
Bower et al. ApJ,2016
First trial with EAVN campaign 2017 data
Obs. Date Sources Freq.
a17077a Mar 18 UT12:45-19:45 M87 K
a17078a Mar 19 UT11:40-18:40 M87 Q
a17086a Mar 27 UT13:10-23:10 M87+SgrA Q
a17093a Apr 3 UT13:20-23:25 M87+SgrA K
a17094a Apr 4 UT12:35-22:35 M87+SgrA Q
a17099a Apr 9 UT12:20-22:20 M87+SgrA Q
a17104a Apr 14 UT12:00-22:00 M87+SgrA Q
a17107a Apr 17 UT11:45-18:45 M87 K
a17108a Apr 18 UT11:40-21:40 M87+SgrA Q
a17114a Apr 24 UT09:20-16:20 M87 K
a17115a Apr 25 UT09:15-16:15 M87 Q
a17116a Apr 26 UT15:55-21:55 SgrA Q
a17130a May 10 UT08:20-17:20 M87 K
a17131a May 11 UT08:15-17:15 M87 Q
a17145a May 25 UT14:10-20:12 SgrA Q
a17146a May 26 UT07:20-14:20 M87 Q
Obs summary of A17086ADate March 27, 2017Stations KaVA+TianmaFreq 43G, Q band in LCPBandwidth 8IF*32MHz=256 MHzScan length 780 sec eachRaw data transfer KJCC to SHAO
Correlated with SHAO-DiFX for:1. Radio profile of magnetar2. Imaging magnetar with pulsar binning/gating3. …
Profile of magnetar
Raw profile from correlator
0 100 200 300 400 500 600 700 800 900 1000
-5
0
5
10
15
20
x 10-3 Data and Fits
0 100 200 300 400 500 600 700 800 900 1000-0.01
-0.005
0
0.005
0.01Residuals
y vs. x
Profile at 43G
Single pulses vs. time
S. Chatterjee et al. 2018
SNR will be improved by 2 times with pulsar gating.
Chandra monitoring of magnetar J1745-2900MJD 56424
MJD 57588
~3.5 yr Coti Zelati, et al, MNRAS, 2017
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1-0.01
-0.005
0
0.005
0.01
0.015
0.02
Profile from Chandra
Raw profile from correlator
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1-0.01
-0.005
0
0.005
0.01
0.015
0.02
Image of Magnetar
Fringes of “magnetar” Fake image of magnetar
Phase center @ magnetar
-5 0 5-0.2
0
0.2
0.4
0.6
0.8
1
1.2
Image of Magnetar
Response of two element interferometer
single dish beam
two element beam
SgrA*Magnetar
Image of Magnetar, a second try
In beam phase-referencing calibration Phase center A @ SgrA*, Phase center B @ Magnetar
SgrA* Dirty map of phase-referenced Magnetar
Summary
1. Magnetar(J1745-2900) seems could be detected by EAVNin the Q band, K band data under check.
2. A good model of SgrA* is important to subtract itscontamination to the beam, testing the model?
3. Data processing in other epochs are still ongoing.4. Dig the GC area beginning with Magnetar.
Thank you !