Athena+, ESA’s next generation X-ray

observatory

Gregor RauwHigh-Energy Astrophysics Group Liège University

on behalf of the Athena+ coordination group

The X-ray Universe today

X-ray astrophysics provides a complementary view of the Universe, revealing highly energetic phenomena.

Crab Nebula

Sirius B

Orion

Moon

XMM-Newton (ESA) and Chandra (NASA) are now in orbit for more than 10 years and have deeply changed our view of the X-ray Universe.

Among the many discoveries:

• Establishing charge-exchange as the mechanism for X-ray emission of comets

• Quantitative diagnostics of hot plasma in the coronae and winds of stars

• Images of the particle acceleration shocks in supernova remnants

• Direct measurement of rotation of black holes and neutron stars

• Resolving the cosmic X-ray background into discrete sources, mostly AGN

• Contributions to the study of dark matter and dark energy via observations of galaxy clusters.

• …

Cas A M82 NGC6231 Cen A

Where are the hot baryons and how do they evolve?

The science to be addressed by Athena+

How do black holes grow and shape the Universe?

The life cycle of matter and energy in the local Universe

High z groups and clusters.

Evolution of hot baryons.

Missing baryons at low z.

Physics of clusters and groups.

AGN feedback.

Accretion physics.

Obscured accretion and galaxy formation.

Growth of SMBHs.

Star formation and evolution.

Compact Objects

SNRs and the ISM

Solar System and exo-planets.

Diagnose hot/energetic cosmic plasmas in a wide variety of astrophysical environments using spatially resolved medium and high-resolution X-ray spectroscopy

• Where are the hot baryons and how do they evolve?• Reveal and map the first virialized baryonic structures• Determine their dynamical, thermal and chemical evolution E.g. measure the chemical composition of the hot plasma in galaxy clusters as a function of z.

• Complete the census of baryons in the local Universe Trace large-scale-structures and detect the WHIM via high resolution X-ray spectroscopy

• Understand the physics of clusters and groups Determine intra-cluster gas velocities as a function of z via imaging X-ray spectroscopy.

Cosmic Web Cluster Physics

Accretion physics High z SMBHCosmic Feedback Obscured accretion

• Reveal the causes and effects of AGN feedback

• Understand the physics of accretion onto compact objects

X-ray tomography of inner accretion disk, determination of the spin rate of black holes (Fe K line shape), hot spot tracking (short-term variability of Fe Kα line).

• Track obscured accretion through the ages

• Perform a census of black hole growth at high redshift

• How do black holes grow and shape the Universe?

• Life cycle of matter and energy in the local Universe• Star formation and evolution Young stars, stellar winds, stellar activity

• End points of stellar evolution X-ray binaries, neutron star, pulsars, white dwarfs

• Supernova remnants and the interstellar medium Disentangle the 3-D structure of SNR via high-resolution integral field spectroscopy, study the acceleration of particles by the SNR shock through the resulting non-thermal emission.

• The Solar System and exo-planets

Charge ExchangeStellar ActivityCompact Objects SNRs

A few more specific examplesWind-wind collisions in massive binaries: dynamics of hot gas well traced by Fe K line.

E.g. colliding winds in WR140: diagnose the physics of the innermost parts of the wind-wind interaction.

But also: study X-ray emission and variability of single massive stars, Doppler-map their magnetospheres,…

A few more specific examplesX-ray emission from planets of the Solar System. E.g. Jupiter (emission due to charge exchange, solar X-ray scattering and electron bremsstrahlung)

Integral field spectroscopy with Athena+ will resolve the disk and auroral charge exchange emissions and resolve the charge exchange ions (hence specify their origin)

But also: look for Saturn’s auroral X-rays, Mars: solar X-ray scattering in the atmosphere, charge-exchange in the exosphere

Athena+ mission concept

Focal plane

Mirror Assembly

Service Module

12m Fixed Focal Length

Sensitivity ~ 30 times better than XMM: stacked Si pore optics, 5” (3”) resolution

Payload: Wide Field Imager (WFI), X-ray Integral Field Unit (X-IFU) microcalorimeter.

L2 orbit, 5yr nominal lifetime (starting 2028)

Athena+ requirementsRequirement Driver

Effective Area 2m2@ 1 keV (goal 2.5m2)

0.25m2 @ 6 keV (goal 0.3m2)

Hot BaryonsBlack hole evolutionAccretion Physics

Angular Resolution

5” (goal of 3”) Black Hole EvolutionHot Baryons

Fields of view WFI: 40’ diameter (goal 50’)X-IFU: 5’ x 5’ (goal 7’ x 7’)

Hot BaryonsBlack Hole Evolution

Spectral resolution

150 eV @ 6 keV (WFI)2.5 eV (X-IFU) goal 1.5 eV

Black Hole EvolutionHot Baryons

Count rate capability

>1 Crab Accretion Physics

Timing resolution

50 ms Accretion Physics

TOO response 8 hours (2 hours goal) Hot Baryons

• Find out more about Athena+: http://www.the-athena-x-ray-observatory.eu• And sign up to support the project!• Athena+ Open Meeting:1-2 July in Paris

Athena+ white paper in response to ESA call for L2/L3 currently in preparation (due 24 May).

Athena+ will be the most sensitive X-ray observatory ever. It will lead to substantial breakthroughs in many different fields of astrophysics.