The Erosita All-Sky Survey - Stars in X-Rays

The eROSITA all-sky survey - Stars in X-rays ...

Jan Robrade

Hamburger Sternwarte

The X-ray Universe 2017 Rome, 6 - 9 June eROSITA (extended Roentgen Survey with an Imaging Telescope Array)

eRASS: eROSITA All-Sky Survey data acquisition: 2019 – 2022 −14 −2 −1 lim. FX ≈ 1 × 10 erg cm s

eROSITA on SRG talk by P. Predehl (Thursday morning) SRG Spacecraft

eROSITA/SRG – launch 2018, L2 halo orbit all-sky survey (4 yr, sky-split D/Ru) + pointed phase (3.5 yr) 7 co-aligned X-ray telescopes, FOV 1.03◦ Ø 0.3 – 10.0 keV, HEW 15/28 00, eﬀ. area@1keV 2400/1400 cm2

Jan Robrade (Hamburger Sternwarte) eROSITA & Stars 06.06.2017 2 / 10 eRASS and stars

’eRASS sensitivity with two Suns’ (adapted from Wright et al. 2010) eRASS (black line) vs.

’The X-ray HRD’ (G¨udel2004) ROSAT: survey+pointings (dots) Chandra: CDF-N, ChaMP, COSMOS (crosses) eRASS detection limit: 24 2 −1 LX ≈ 1.0 × 10 × d (pc) [erg s ]

Jan Robrade (Hamburger Sternwarte) eROSITA & Stars 06.06.2017 3 / 10 eRASS and stellar population models

eROSITA X-ray stars (all, 0.5-2.0 keV)

ns00000 Besancon model: 4 ns00090 ns00180 (RASS, Guillout+ 1996) ns05000 ns05180 3 ns10000 ∼ 0.7 million X-ray stars ns10180 2 ns20000 > 50 per deg (disk), ns20180 2 ns30000 2 ns30180 ∼ 6 per deg (poles) ns50000 ns50180 1 (lim. logS = -1.9 [cts/s], 20 cts/1650s) ns70000

log N (1/deg^2) ns70180 ns90000 0

1 Stellar surface densities at var. galactic lat./lon. 3.0 2.5 2.0 1.5 1.0 0.5 0.0 log S (cts/s)

Simulations are based on the Besancon Stellar X-ray population model. Image by J. Robrade.

3 age x 6 star groups (0.15/1.0/10 Gyr, A to late M, ’standard’ coronal sources) strong overall contribution from young stars (∼ 250000)

Jan Robrade (Hamburger Sternwarte) eROSITA & Stars 06.06.2017 4 / 10 Detecting nearby stars with eROSITA

Nearby young stars - eRASS X-ray horizon Sensitivity at 100 pc (MS): 28.0 HR 8799 TW Hya --> 1kpc early F (5 L ) → log LX/Lbol = -6.3 EK Dra, AB Dor --> 1kpc AT Mic --> 500 pc 1 mid M (0.005 L ) → log LX/Lbol = -3.3 π UMa--> 300 pc AD Leo --> 200 pc ) 1 − s

g r

e F - mid M stars ( 27.5

x L

g Gould Belt SFRs o l ( 140 pc) ≥ Pleiades (130 pc) 27.0 +late A/VLM

26.5 26.0 AB Dor Tuc/Hor β Pic TWA η Cha

0 20 40 60 80 100 Distance (pc) young+nearby (100 pc, 200 Myr) → virtually all F to mid M stars closer X-ray horizon for late A, VLM stars and older populations

very nearby - RECONS 10 pc sample :: > 300 stars (4-6-20-44-248, A-F-G-K-M)

Jan Robrade (Hamburger Sternwarte) eROSITA & Stars 06.06.2017 5 / 10 SFRs & T Tauri stars

CTTS - WTTS - ZAMS

strong X-ray emission in all YSOs all-sky & harder energy range ideal

−400 Ori OB1b −1 SFRs at 100 – 500 pc (Gould belt) Ori OB1c 10 km s Per −200 Ori CTTS: accretors Ori OB1a Cas Col 121 Per OB2 Cep OB2 Tau Cep Vela OB2 α Per WTTS: weak/no accretion or disks 0 Vela X (pc) Cep OB6 post TTs/ZAMS Tr 10 LCC Sun Lac OB1 200 UCL Oph US Massive SFRs in Milky Way, GC Aqu 400 −600 −400 −200 0 200 400 600 800 collective X-ray emission Y (pc) Nearby SFRs and Gould Belt

Jan Robrade (Hamburger Sternwarte) eROSITA & Stars 06.06.2017 6 / 10 More rare stars

Massive + Intermediate mass stars O + early B stars, Lx/Lbol relations WR, LBV, magn. massive stars HAeBe stars : coronae, jets, MCWS, (companions) ApBp stars : MCWS, magnetic disks, (companions)

Stelzer et al. (2009) Ultracool dwarfs (M7+) X-ray bright UCD population in solar vicinity (. 30 pc) VLM stars (fully convective) young or massive/hot BDs

Williams et al. (2014)

Jan Robrade (Hamburger Sternwarte) eROSITA & Stars 06.06.2017 7 / 10 Beyond detections - spectral properties

AT Mic (2ks eRASS) −1 keV −1 normalized counts s 0.01 0.1 1 10

0.5 1 2 5 Energy (keV) AT Mic - simulated eRASS spectrum (27000 counts)

about 50000 (5000) stars with & 200 (1000) counts coronal properties of X-ray brighter targets multi-band HR classiﬁcation for many other sources

Jan Robrade (Hamburger Sternwarte) eROSITA & Stars 06.06.2017 8 / 10 Beyond detections - time-dependent properties

9 10 11 12 13 14 15 16 17 18 19 20 21 4.0 LP 412-31 (M8) COUP 1568R: 3.99 Cts: 89438 M: 2.55 3.5 )

2000 4000 1

− 3.0 s

s 2.5

1500 3000 t c

( 2.0

1000 2000 e t 1.5 a R

Counts / K sec 1.0

500 1000 counts [approx.] 0.5 0 0 0.0 0 5 10 15 20 25 30 35 0 2•105 4•105 6•105 8•105 1•106 Time [sec.] 2.0 61 Cyg A - XMM SCR J1845-6357 (M8.5)

2.0 )

1 1.5 ] − 1 − s s

s g r t

e 1.5 c [ 1.0

( 7

2 0 e 1 t

X a

L 1.0 R 0.5

0.5 0.0 2002 2004 2006 2008 2010 2012 2014 2016 0 5 10 15 Time (year) Time (ks)

X-ray light curves – left: nearby young stars; middle: A0p star, CTTS, K dwarf; right: M dwarfs, UCDs

light curves on multiple timescales + transient sources 4 yr survey: 8 sky-scans (0.5 yr) with 6 scans/day (40 s each) X-ray variability, ﬂare statistics, activity cycles...

Jan Robrade (Hamburger Sternwarte) eROSITA & Stars 06.06.2017 9 / 10 Summary and synergies

The eROSITA all-sky survey - an unprecedented view of the X-ray sky

RASS =⇒ eRASS: about factor 20 higher sensitivity plus variability, higher spatial resolution, X-ray spectral characteristics...

volume complete samples, full stellar populations, large object numbers

Synergies: most eROSITA stars are optically bright (V . 15 mag) Gaia :: distances, 3-D space motions, identiﬁcations etc. MWL data and aux. catalogs :: stellar properties, activity+age indicators, planet hosts etc.

Interested in collaborating? Give us a note...

Jan Robrade (Hamburger Sternwarte) eROSITA & Stars 06.06.2017 10 / 10