Detecting new supernova remnants with GLEAM Natasha Hurley-Walker Curtin University @ColourfulCosmos
Supernova remnants Artist’s impression Credit: ESA/Hubble (L. Calçada) 10 53 ergs gravitational energy Stars with M > 8M Θ end in core-collapse ● ● → 10 51 kinetic energy deposited into stellar envelope ● supernovae (Type II, Ib/c) Ejected with v ~ 5000 km/s ● White dwarfs disrupt binary companion, accrete, ● Shock wave produces synchrotron and X-ray emission ● supernova (Type Ia) 25th February 2019
Impact on the interstellar medium Inject metals into the ISM, measurable ● within our own solar system (e.g. Vanhala & Boss 2002) l Disrupt star formation in nearby a ● c molecular clouds i t p o (e.g. Desai et al. 2010) Heat ISM to 10 6 K ● Fast shocks destroy H 2 ● (Vanhala & Cameron 1998) SN 1054 (Crab) SN 1006 Slow shocks form CO, OH, H 2 O, CH + , ● create and destroy dust grains (see review: Sarangi 2018) Accelerate cosmic rays at shock fronts ● y a (Blandford & Ostriker 1978; Bell 1978; observational r - evidence e.g. Sano et al. 2018) X Some host pulsar wind nebulae ● (PWNe) 25th February 2019
Radio morphologies Blow-out Shell / barrel 295 known (Green 2017) Plerion ● Expect 3x more ● (from O,B star counts, SN rates in Local Group, predicted synch lifetimes) Multi-shell Helical nebula 95% of SNR detected via radio ● Selection effects? ● Resolution - Field-of-view / survey speed - Surface brightness sensitivity - Quality of ancillary IR data - Frequency of search - Dubner & Giacani 2015 Bandwidth of search - 25th February 2019
Detecting radio supernova remnants Non-thermal: Radio emission Thermal: Radio+ infrared emission Anderson et al. (2017) Brogan et al. (2006) 25th February 2019
GaLactic and Extragalactic All-sky MWA survey Dec < 30 º , 72 – 231 MHz, resolution ~ 2’, via 4 weeks with MWA 128T Publication highlights Riseley et al. 2018: The POlarised GLEAM Survey (POGS) I: First Results from a Low-Frequency Radio Linear Polarisation Survey of the Southern Sky ● For et al. 2018: A multifrequency radio continuum study of the Magellanic Clouds - I. Overall structure and star formation rates ● Su et al. 2018: Galactic synchrotron distribution derived from 152 H II region absorption features in the full GLEAM survey ● Galvin et al. 2018: The spectral energy distribution of powerful starburst galaxies - I. Modelling the radio continuum ● Callingham et al 2017: Extragalactic Peaked-spectrum Radio Sources at Low Frequencies ● George et al. 2017: A study of halo and relic radio emission in merging clusters using the Murchison Widefield Array ● Kapinska et al. 2017: Spectral Energy Distribution and Radio Halo of NGC 253 at Low Radio Frequencies ● Murphy et al. 2017: Low-Frequency Spectral Energy Distributions of Radio Pulsars Detected with the Murchison Widefield Array ● Murphy et al. 2017: A search for long-time-scale, low-frequency radio transients ● Su et al. 2017: Galactic synchrotron emissivity measurements between 250° < l < 355° from the GLEAM survey with the MWA ● Hurley-Walker et al. 2017: GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey - I. A low-frequency extragalactic catalogue ● Callingham et al. 2016: Low radio frequency observations and spectral modelling of the remnant of Supernova 1987A ● Lenc et al. 2016: Low-frequency Observations of Linearly Polarized Structures in the Interstellar Medium near the South Galactic Pole ● Hindson et al 2016: A Large-Scale, Low-Frequency Murchison Widefield Array Survey of Galactic H ii Regions between 260 < l < 340 ● Wayth et al. 2015: GLEAM: The GaLactic and Extragalactic All-Sky MWA Survey ● 25th February 2019
GLEAM Data ● Images ● gleam-vo.icrar.org or SkyView ● 8-MHz sub-bands from 72 – 231 MHz ● Wideband 30 – 60 MHz images ● Catalogue ● 307,455 sources ● ~35mJy/beam flux limit ● 20 flux densities ● Spectral indices for ~70% of sources Red = 72 – 103 MHz Green = 103 – 134 MHz Blue = 139 – 170 MHz 25th February 2019
GLEAM Data ● Images ● gleam-vo.icrar.org or SkyView ● 8-MHz sub-bands from 72 – 231 MHz ● Wideband 30 – 60 MHz images ● Catalogue ● 305,455 sources ● ~35mJy/beam flux limit ● 20 flux densities ● Spectral indices for ~70% of sources Callingham et al. (2017) 25th February 2019
(Current) Sky coverage 25th February 2019
GLEAM: Galactic Plane Imaging BEFORE Access to Better wider areas deconvolution Removed Accurate via image of large-scale flux improved AFTER structure artefacts calibration peeling (Multiscale WSClean) RMS 10 – 20 mJy/beam @ 200MHz Hurley-Walker et al. (submitted): GLEAM GP across 345° < l < 60°, 180° < l < 240° 25th February 2019
The GLEAM view of SNRs GLEAM 200MHz 25th February 2019
The GLEAM view of SNRs GLEAM 200MHz 25th February 2019
The GLEAM view of SNRs GLEAM RGB (88/118/154)MHz GLEAM 200MHz 25th February 2019
The GLEAM view of SNRs GLEAM RGB (88/118/154)MHz GLEAM 200MHz 25th February 2019
The GLEAM (and WISE) view of SNRs Widefield Infrared Survey Explorer (WISE) RGB 22μm emission = thermal small dust grains (4.6/12/22)μm 12μm emission = PAHs fluorescing from UV 25th February 2019
Measuring SNRs 25th February 2019
Following up SNR candidates Green (2017) 250 candidates ● 136 in imaged region ● 14 from MAGPIS - 101 from other sources - http://www.mrao.cam.ac.uk/surveys/snrs/snrs.info.html#S23 25th February 2019
Confirming candidates: G353.3-1.1 Parkes, 2.4 GHz (Duncan+95) GLEAM GP RGB α=-0.85, S 200MHz ~100Jy PSR → SNR diameter = 71pc → SNR age > 130,000 yr 25th February 2019
Understanding candidates: MGPS (843 MHz) GLEAM 200MHz GLEAM RGB (88/118/154)MHz 25th February 2019
Understanding candidates: G3.1–0.7 MGPS (843 MHz) GLEAM 200MHz GLEAM RGB (88/118/154)MHz VRO42.05.01 Landecker 1982 Density of ISM around A is 32x that around B Blow-out 25th February 2019
Falsifying candidates: G19.00-0.35 GLEAM RGB (88/118/154)MHz WISE RGB (8/12/22)μm GLEAM 200MHz Proposed by Gosachinski 1985 Clearly a (complex of) Hii region(s)! 25th February 2019
Falsifying candidates: G19.00-0.35 GLEAM RGB (88/118/154)MHz WISE RGB (8/12/22)μm GLEAM 200MHz See also Helfand et al. (2006): 31/49 candidates are actually HII regions 25th February 2019
Submitted! 25th February 2019
Known SNRs (green) 345° < l < 60° 25th February 2019
Known SNRs (green), known candidates (cyan), THOR candidates (red) T he H I/ O H/ R RL survey (Anderson+2017) 345° < l < 60° 25th February 2019
Known SNRs (green), known candidates (cyan), THOR candidates (red), new candidates (magenta) 345° < l < 60° 25th February 2019
Known SNRs (green), known candidates (cyan), THOR candidates (red), new candidates (magenta) 180° < l < 240° 25th February 2019
27 new candidate SNRs Filled 25th February 2019
New SNRs Hurley-Walker et al. (submitted): New candidate SNRs from GLEAM 25th February 2019
A few compact SNR (<10’) G 351.0 - 0.6 GLEAM RGB (88/118/154)MHz WISE RGB (8/12/22)um MGPS (843MHz) 25th February 2019
Large, diffuse SNR G 350.8 + 0.7 GLEAM RGB (88/118/154)MHz WISE RGB (8/12/22)um MGPS (843MHz) 25th February 2019
Large, diffuse SNR G 21.8+0.2 GLEAM RGB (88/118/154)MHz WISE RGB (8/12/22)um Effelsberg (2.7GHz) 25th February 2019
Large, diffuse SNR G 25.4-1.9 GLEAM RGB (88/118/154)MHz WISE RGB (8/12/22)um Effelsberg (2.7GHz) 25th February 2019
High-latitude SNR G 0.2-9.7 GLEAM RGB (88/118/154)MHz WISE RGB (8/12/22)um 25th February 2019
A new longitude range . 25th February 2019
Pulsar associations 25th February 2019
G 0.2–9.7 J1825-33 (RRAT) DM = 43 ± 2 cm -3 pc → Dist = 1.24 kpc → diameter = 24 pc SNR age estimate < 9k yr P = 1.27 s No P → no age estimate Position accuracy ~ 15’ → no kick velocity Burke-Spolaor & Bailes 2010) 25th February 2019
G 21.8+0.2 J1831-0952 DM = 247 ± 5 cm -3 pc → Dist = 3.68 kpc → diameter = 70 x 45 pc SNR age estimate ~ 40k – 120k yr P = 67 ms P = 8 x 10 -15 s s -1 Age ~ 130k yr Kick velocity 170 – 490 km s -1 Lorimer et al. 2006 25th February 2019
G 230.5+1.3 J0729-1448 DM = 92 cm -3 pc → Dist = 2.68 kpc → diameter = 47 x 31 pc SNR age estimate ~ 36k yr P = 252 ms P = 10 -13 s s -1 Age ~ 35k yr Kick velocity 180 km s -1 Morris et al. (2002), Petroff et al. (2013) 25th February 2019
G 232.2+2.1 J0734-1559 ( γ -ray pulsar) No DM → No Dist → No diameter → No SNR age estimate P = 155 ms P = 10 -14 s s -1 Age ~ 200k yr Sokolova & Rubstov (2016) 25th February 2019
New pulsars? G 350.8+5.1 Compact source α=-1.4 GLEAM RGB (88/118/154)MHz WISE RGB (8/12/22)um Pulsar? 25th February 2019
Comparisons with known SNR (Green 2017) 25th February 2019
GLEAM-eXtended 25th February 2019
GLEAM-eXtended 25th February 2019
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