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 !