Magnetar (J1745-2900) with EAVN Wu Jiang ( ), SHAO in - - PowerPoint PPT Presentation

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

Motivations

Rare Share Cadence Increase

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, 2015 Apr-May, 2013 Jul-Aug, 2014

Radio spectral index of Magnetar J1745-2900

Torne et al, MNRAS, 2015, 2017 Mar, 2015 Jul-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" projected distance translates in a minimum physical separation d = 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 the in/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 no additional 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 A17086A Date March 27, 2017 Stations KaVA+Tianma Freq 43G, Q band in LCP Bandwidth 8IF*32MHz=256 MHz Scan length 780 sec each Raw data transfer KJCC to SHAO Correlated with SHAO-DiFX for:

• 1. Radio profile of magnetar
• 2. Imaging magnetar with pulsar binning/gating
• 3. …

Profile of magnetar

Raw profile from correlator

100 200 300 400 500 600 700 800 900 1000

• 5

5 10 15 20 x 10

• 3

Data and Fits 100 200 300 400 500 600 700 800 900 1000

• 0.01
• 0.005

0.005 0.01 Residuals

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 J1745-2900

MJD 56424 MJD 57588

~3.5 yr Coti Zelati, et al, MNRAS, 2017

• 0.01
• 0.005

Profile from Chandra Raw profile from correlator

• 0.01
• 0.005

Image of Magnetar

Fringes of “magnetar” Fake image of magnetar

Phase center @ magnetar

• 5

5

• 0.2

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 EAVN

in the Q band, K band data under check.

• 2. A good model of SgrA* is important to subtract its

contamination 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 !