The Square Kilometre Array Science Cases (CosmoAndes 2018)
0 likes105 views
The Square Kilometre Array (SKA) is an international project to build the world's largest radio telescope, aimed at exploring various astronomical phenomena. With its construction phases spanning from 2019 to mid-2020s, it seeks to address crucial cosmic questions such as galaxy evolution, cosmic magnetism, and the nature of dark energy. The SKA will employ advanced technology in a collaboration of over 600 scientists and engineers from multiple countries, leveraging its immense capabilities to enhance our understanding of the universe.
The Square Kilometre Array Science Cases (CosmoAndes 2018)
- 1. The Square Kilometre Array Science Cases Juande Santander-Vela SKA SW Systems Engineer SQUARE KILOMETRE ARRAY Exploring the Universewith the worlds’ largest radio telescope
- 2. Disclaimer! • I’m half engineer, half astronomer • When I play the astronomer card, I’m mostly an observational astronomer working on the nature vs nurture debate, using isolated galaxies, not necessarily in voids! • The other part is very much an electronics, DSP, software and systems engineer Exploring the Universewith the worlds’ largest radio telescope Not a cosmologist, sorry!
- 3. SKA Observatory Vision Exploring the Universewith the worlds’ largest radio telescope 3 sites 2 telescopes 1 observatory Design Phase: ~ €200M; 600 scientists+engineers, 80% complete SKA Phase 1 (SKA1) Construction: 2019 – 2025 Construction cost cap: €674.1M (2016 inflation-adjusted) Operations cost: (estimate) €89M/yr MeerKAT integrated Observatory Development Programme (€20M/year planned) SKA Regional centres out of scope of centrally-funded SKAO. SKA Phase 2: start mid-2020s ~2000 dishes across 3500km of Southern Africa Major expansion of SKA1-Low across Western Australia >50 years lifetime! Drives need for reliability, and adaptability
- 4. SKA Organisation Exploring the Universewith the worlds’ largest radio telescope ! Australia (DoI&S) " Canada (NRC-HIA) # China (MOST) $ India (DAE) % Italy (INAF) & Netherlands (NWO) ' New Zealand (MED) ( South Africa (DST) ) Sweden (Chalmers) * UK (BEIS/STFC) In discussion with: + Germany , France - Portugal . Spain / Switzerland 0 Japan 1 South Korea In the process of becoming an Inter- Governmental Organisation
- 5. SKA1 Design Consortia Exploring the Universewith the worlds’ largest radio telescope
- 6. SKA1-Low locations 1600 km N ➤ ➤ N Data SIO, NOAA, U.S. Navy, NGA, GEBCO Data SIO, NOAA, U.S. Navy, NGA, GEBCO Image Landsat / Copernicus Image Landsat / Copernicus SKA1-Mid locations 500 km N ➤ ➤ N Image Landsat / Copernicus Image Landsat / Copernicus Data SIO, NOAA, U.S. Navy, NGA, GEBCO Data SIO, NOAA, U.S. Navy, NGA, GEBCO SKA1 Sites Exploring the Universewith the worlds’ largest radio telescope
- 7. SKA Sites: RFI Exploring the Universewith the worlds’ largest radio telescope SMOS L-band (1-2 GHz)
- 8. SKA1 Telescopes Exploring the Universewith the worlds’ largest radio telescope SKA1-LOW: 50 – 350 MHz Phase 1: ~130,000 antennas across 65km SKA1-Mid: 350 MHz – 24 GHz Phase 1: 200 15-m dishes across 150 km More information to be provided by SKA Design’s talk
- 9. What science does the SKA cater for? Exploring the Universewith the worlds’ largest radio telescope
- 10. 1991ASPC...19..428W SKA: The Hydrogen Array Early concept stated in in 1990 by P.N. Wilkinson Exploring the Universewith the worlds’ largest radio telescope https://ui.adsabs.harvard.edu/#abs/1991ASPC...19..428W/abstract
- 11. 1991ASPC...19..428W SKA: The Hydrogen Array Early concept stated in in 1990 Core science already established: • Neutral Hydrogen from z=1 to 10 • Continuum at 0.1 µJy 1σ noise level • Pulsar searches and timing across the galaxy Exploring the Universewith the worlds’ largest radio telescope https://ui.adsabs.harvard.edu/#abs/1991ASPC...19..428W/abstract
- 12. Two volumes, 135 Chapters, 2000 pages The Current SKA Science Book Exploring the Universewith the worlds’ largest radio telescope 8.8 kg!
- 13. Two volumes, 135 Chapters, 2000 pages The Current SKA Science Book Exploring the Universewith the worlds’ largest radio telescope https://www.skatelescope.org/ books/ https://pos.sissa.it/cgi-bin/reader/conf.cgi?confid=215
- 14. SKA1 SKA2 The Cradle of Life & Astrobiology Proto-planetary disks; imaging inside the snow/ice line (@ < 100pc), Searches for amino acids. Proto-planetary disks; sub-AU imaging (@ < 150 pc), Studies of amino acids. Targeted SETI: airport radar 10^4 nearby stars. Ultra-sensitive SETI: airport radar 10^5 nearby star, TV ~10 stars. Strong-field Tests of Gravity with Pulsars and Black Holes 1st detection of nHz-stochastic gravitational wave background. Gravitational wave astronomy of discrete sources: constraining galaxy evolution, cosmological GWs and cosmic strings. Discover and use NS-NS and PSR-BH binaries to provide the best tests of gravity theories and General Relativity. Find all ~40,000 visible pulsars in the Galaxy, use the most relativistic systems to test cosmic censorship and the no-hair theorem. The Origin and Evolution of Cosmic Magnetism The role of magnetism from sub-galactic to Cosmic Web scales, the RM-grid @ 300/deg2. The origin and amplification of cosmic magnetic fields, the RM- grid @ 5000/deg2. Faraday tomography of extended sources, 100pc resolution at 14Mpc, 1 kpc @ z ≈ 0.04. Faraday tomography of extended sources, 100pc resolution at 50Mpc, 1 kpc @ z ≈ 0.13. Galaxy Evolution probed by Neutral Hydrogen Gas properties of 10^7 galaxies, z ≈ 0.3, evolution to z ≈ 1, BAO complement to Euclid. Gas properties of 10^9 galaxies, z ≈ 1, evolution to z ≈ 5, world-class precision cosmology. Detailed interstellar medium of nearby galaxies (3 Mpc) at 50pc resolution, diffuse IGM down to N_H < 10^17 at 1 kpc. Detailed interstellar medium of nearby galaxies (10 Mpc) at 50pc resolution, diffuse IGM down to N_H < 10^17 at 1 kpc. Headline SKA Science (1/2) Exploring the Universewith the worlds’ largest radio telescope
- 15. SKA1 SKA2 The Cradle of Life & Astrobiology Proto-planetary disks; imaging inside the snow/ice line (@ < 100pc), Searches for amino acids. Proto-planetary disks; sub-AU imaging (@ < 150 pc), Studies of amino acids. Targeted SETI: airport radar 10^4 nearby stars. Ultra-sensitive SETI: airport radar 10^5 nearby star, TV ~10 stars. Strong-field Tests of Gravity with Pulsars and Black Holes 1st detection of nHz-stochastic gravitational wave background. Gravitational wave astronomy of discrete sources: constraining galaxy evolution, cosmological GWs and cosmic strings. Discover and use NS-NS and PSR-BH binaries to provide the best tests of gravity theories and General Relativity. Find all ~40,000 visible pulsars in the Galaxy, use the most relativistic systems to test cosmic censorship and the no-hair theorem. The Origin and Evolution of Cosmic Magnetism The role of magnetism from sub-galactic to Cosmic Web scales, the RM-grid @ 300/deg2. The origin and amplification of cosmic magnetic fields, the RM- grid @ 5000/deg2. Faraday tomography of extended sources, 100pc resolution at 14Mpc, 1 kpc @ z ≈ 0.04. Faraday tomography of extended sources, 100pc resolution at 50Mpc, 1 kpc @ z ≈ 0.13. Galaxy Evolution probed by Neutral Hydrogen Gas properties of 10^7 galaxies, z ≈ 0.3, evolution to z ≈ 1, BAO complement to Euclid. Gas properties of 10^9 galaxies, z ≈ 1, evolution to z ≈ 5, world-class precision cosmology. Detailed interstellar medium of nearby galaxies (3 Mpc) at 50pc resolution, diffuse IGM down to N_H < 10^17 at 1 kpc. Detailed interstellar medium of nearby galaxies (10 Mpc) at 50pc resolution, diffuse IGM down to N_H < 10^17 at 1 kpc. Headline SKA Science (1/2) Exploring the Universewith the worlds’ largest radio telescope
- 16. SKA1 SKA2 The Transient Radio Sky Use fast radio bursts to uncover the missing "normal" matter in the universe. Fast radio bursts as unique probes of fundamental cosmological parameters and intergalactic magnetic fields. Study feedback from the most energetic cosmic explosions and the disruption of stars by super-massive black holes. Exploring the unknown: new exotic astrophysical phenomena in discovery phase space. Galaxy Evolution probed in the Radio Continuum Star formation rates (10 M_Sun/yr to z ~ 4). Star formation rates (10 M_Sun/yr to z ~ 10). Resolved star formation astrophysics (sub-kpc active regions at z ~ 1). Resolved star formation astrophysics (sub-kpc active regions at z ~ 6). Cosmology & Dark Energy Constraints on DE, modified gravity, the distribution & evolution of matter on super-horizon scales: competitive to Euclid. Constraints on DE, modified gravity, the distribution & evolution of matter on super-horizon scales: redefines state- of-art. Primordial non-Gaussianity and the matter dipole: 2x Euclid. Primordial non-Gaussianity and the matter dipole: 10x Euclid. Cosmic Dawn and the Epoch of Reionization Direct imaging of EoR structures (z = 6-12). Direct imaging of Cosmic Dawn structures (z = 12-30). Power spectra of Cosmic Dawn down to arcmin scales, possible imaging at 10 arcmin. First glimpse of the Dark Ages (z > 30). Headline SKA Science (2/2) Exploring the Universewith the worlds’ largest radio telescope
- 17. SKA1 SKA2 The Transient Radio Sky Use fast radio bursts to uncover the missing "normal" matter in the universe. Fast radio bursts as unique probes of fundamental cosmological parameters and intergalactic magnetic fields. Study feedback from the most energetic cosmic explosions and the disruption of stars by super-massive black holes. Exploring the unknown: new exotic astrophysical phenomena in discovery phase space. Galaxy Evolution probed in the Radio Continuum Star formation rates (10 M_Sun/yr to z ~ 4). Star formation rates (10 M_Sun/yr to z ~ 10). Resolved star formation astrophysics (sub-kpc active regions at z ~ 1). Resolved star formation astrophysics (sub-kpc active regions at z ~ 6). Cosmology & Dark Energy Constraints on DE, modified gravity, the distribution & evolution of matter on super-horizon scales: competitive to Euclid. Constraints on DE, modified gravity, the distribution & evolution of matter on super-horizon scales: redefines state- of-art. Primordial non-Gaussianity and the matter dipole: 2x Euclid. Primordial non-Gaussianity and the matter dipole: 10x Euclid. Cosmic Dawn and the Epoch of Reionization Direct imaging of EoR structures (z = 6-12). Direct imaging of Cosmic Dawn structures (z = 12-30). Power spectra of Cosmic Dawn down to arcmin scales, possible imaging at 10 arcmin. First glimpse of the Dark Ages (z > 30). Headline SKA Science (2/2) Exploring the Universewith the worlds’ largest radio telescope
- 18. Sensitivity comparison Exploring the Universewith the worlds’ largest radio telescope
- 19. Survey-speed comparison Exploring the Universewith the worlds’ largest radio telescope
- 20. Resolution comparison Exploring the Universewith the worlds’ largest radio telescope
- 21. Simulated SKA1-Low continuum transit snap-shot dirty image at 140 MHz. Simulated LOFAR continuum transit snap-shot dirty image at 140 MHz. SKA1-Low vs LOFAR Exploring the Universewith the worlds’ largest radio telescope Simulated SKA1-Low continuum transit snap-shot dirty image at 140 MHz. SKA1-Low (simulated @140 MHz) LOFAR (simulated @140 MHz) Single SKA1-Low snap-shot compared to LOFAR-INTL snap-shot
- 22. SKA1-Mid vs VLA Exploring the Universewith the worlds’ largest radio telescope SKA1-Mid (simulated) VLA (A+B+C+D; simulated) Single SKA1-Mid snap-shot compared to combination of snap-shots in each of VLA A+B+C+D
- 23. A selection of cases • The Cradle of Life & Astrobiology • Strong-field Tests of Gravity with Pulsars and Black Holes • The Origin and Evolution of Cosmic Magnetism • Galaxy Evolution probed by Neutral Hydrogen • The Transient Radio Sky • Galaxy Evolution probed in the Radio Continuum • Cosmology & Dark Energy • Cosmic Dawn and the Epoch of Reionization Exploring the Universewith the worlds’ largest radio telescope
- 24. Cradle of Life & AB Exploring the Universewith the worlds’ largest radio telescope
- 25. Cradle of Life & AB Proto-planetary disk processes and characteristic wavelengths for different instruments Exploring the Universewith the worlds’ largest radio telescope
- 26. From Testi et al. “Protoplanetary disks and the dawn of planets with SKA” (2015) SKA1-Mid Band 5
- 27. Cradle of Life AB Line sensitivity simulations The SKA1-Mid can be ~10 times more sensitive to molecular lines from glycine in cold pre-stellar core (such as L1544) Exploring the Universewith the worlds’ largest radio telescope From Testi et al. “Protoplanetary disks and the dawn of planets with SKA” (2015) SKA1-Mid Band 5
- 28. Pulsar science with SKA Exploring the Universewith the worlds’ largest radio telescope
- 29. !
- 31. * ! %! ! , !- .100!#
- 32. !!.! 2.
- 33. ! 1!.! 100
- 34. ! 1! ! !' # + !! 034560432 #
- 35. (!
- 36. !
- 37. $$#%#!$# $! $!
- 38. Pulsar science with SKA Exploring the Universewith the worlds’ largest radio telescope Cumulative distribution of pulsar discoveries; the ramp on the right panel assumes a SKA first light of 2022 From Kramer and Stappers “Pulsar Science with the SKA” (2015)
- 39. SKA and International Pulsar Timing Arrays (IPTA) will be sensitive to the nanoHertz background of gravitational waves from supermassive black hole binaries (SMBHBs) Pulsar science: GWs and PTA Exploring the Universewith the worlds’ largest radio telescope From Jansen et al. “Gravitational wave astronomy with the SKA” (2015)
- 40. 0 2 4 6 8 10 Total observing time span/yr 0.0 0.2 0.4 0.6 0.8 1.0 Fraction of simulations IPTA Background Single source Any detection 0 2 4 6 8 10 Total observing time span/yr 0.0 0.2 0.4 0.6 0.8 1.0 Fraction of simulations SKA1 − 50% Background Single source Any detection 0 2 4 6 8 10 Total observing time span/yr 0.0 0.2 0.4 0.6 0.8 1.0 Fraction of simulations SKA1 (BD) Background Single source Any detection 0 2 4 6 8 10 Total observing time span/yr 0.0 0.2 0.4 0.6 0.8 1.0 Fraction of simulations SKA2 Background Single source Any detection 0 2 4 6 8 10 Total observing time span/yr 0 2 4 6 8 10 S/N SKA1 (BD) Background Single source 0 2 4 6 8 10 Total observing time span/yr 0 10 20 30 40 50 S/N SKA2 Background Single source With 50% of SKA1-Mid, only after 10 years there will be signs of detection with 50% chance; full SKA1 reaches 50% for any event in ~4 years, and full SKA2 in less than two years. GW detection probability Exploring the Universewith the worlds’ largest radio telescope From Jansen et al. “Gravitational wave astronomy with the SKA” (2015)
- 41. Cosmology Dark Energy Exploring the Universewith the worlds’ largest radio telescope
- 42. Cosmology Dark Energy • SKA2 is the end game: the mythical billion galaxy survey • Santos et al. “Cosmology from a SKA HI intensity mapping survey” (2015): «All-sky neutral hydrogen (HI) intensity mapping surveys that do not detect individual galax- ies but only the integrated HI emission of galaxies in each pixel, together with very accurate redshifts at each tomographic slice.» → large-scale structure tomography • Jarvis et al. “Cosmology with SKA Radio Continuum Surveys” (2015): «All- sky radio continuum surveys that detect radio galaxies through their total emission out to very high redshift.» → probe of large-scale structure Exploring the Universewith the worlds’ largest radio telescope Make SKA1 competitive
- 43. Camera, Harrison, Bonaldi, Brown Weak Lensing • Extensive simulations by the Manchester group • SKA1 continuum weak lensing is competitive with DES (auto/cross-corr) • Radio x optical weak lensing cross-correlation is a powerful way of removing important systematics (hard to trust DES/LSST weak lensing results without SKA1!) • Bayesian approach allows to extract a large number of redshifts using the HI line in combination with continuum information (Harrison et al.) Exploring the Universewith the worlds’ largest radio telescope
- 44. Cosmic Dawn EoR Exploring the Universewith the worlds’ largest radio telescope
- 45. Cosmic Dawn EoR Exploring the Universewith the worlds’ largest radio telescope From Koopmans et al. “The Cosmic Dawn and Epoch of Reionization with the Square Kilometre Array” (2015) “When was the last time your baryons did something interesting?” Sangeeta Malhotra
- 46. Cosmic Dawn EoR • Cosming Dawn and EoR go from z ~ 6 to z ~ 30 (350 MHz to 50 MHz) → SKA1‑Low range • Observing strategies: • Direct imaging (a.k.a. tomography) of neutral hydrogen down to the 1σ ≈ 1mK brightness temperature level on 5-arcmin scales at z ≈ 6, rising to degree scales at z=28. • Statistical (including power-spectrum) methods to variance levels 1σ ≈ 0.01 − 1 mK2 over the redshift regime z=6-28, respectively, at k0.1 Mpc−1 and to k1 Mpc−1 at z 15. • 21-cm absorption line observations against high-z radio sources, if present, with 1- 5 kHz spectral resolution (2-10 km/s at z=10) with S/N5 on 1 mJy. Exploring the Universewith the worlds’ largest radio telescope All of them require control of thermal noise only possible with SKA1-Low
- 47. Cosmic Dawn EoR • Deep survey • 1000hr integrations on 5 separate 20-square degree windows → 100 square-degrees • 50-200MHz frequency range with 0.1 MHz spectral resolution (150 MHz bandwidth, ~1500 channels) • SKA1-Low multi-beaming can allow this to be done in 2500h with 2 beams (up to 300 MHz bandwidth; makes the two beams identical) Exploring the Universewith the worlds’ largest radio telescope
- 48. Cosmic Dawn EoR • Medium+Shallow Survey • Medium survey: 50 times 100-hr integrations covering 1,000 square degrees • Shallow survey: 500 times 10-hour integrations covering 10,000 square degrees; precedes the medium survey to select targets • 50-200MHz frequency range with 0.1 MHz spectral resolution (150 MHz bandwidth, ~1500 channels) • SKA1-Low multi-beaming can allow this to be done in 2500h with 2 beams (up to 300 MHz bandwidth; makes the two beams identical) Exploring the Universewith the worlds’ largest radio telescope
- 49. Cosmic Dawn EoR • 21-cm absorption survey • 21-cm absorption line spectra from (rare) radio sources at z 6 — probes very small scales (i.e. k ∼ 1000 Mpc−1) or virialized structures (mini-haloes) • state, thermal history and chemistry of the IGM, study the first stars, black holes and galaxies and constrain cosmology, the physics of dark matter and gravity. • Deep 1000-hrs integrations on selected sources with a flux of 1 mJy (selected from Deep Survey fields) • 1-5 kHz resolution (requires more than 64k channels) over the 50-200 MHz frequency range (z ∼ 6 − 28). Exploring the Universewith the worlds’ largest radio telescope
- 50. How will science data get to scientists? Exploring the Universewith the worlds’ largest radio telescope
- 51. SKA Regional Centres Exploring the Universewith the worlds’ largest radio telescope
- 52. SKA Observatory SRC 1 SRC 2 SRC n SRC 3 SKA Regional Centre Alliance Users SRC Science Gateway Exploring the Universewith the worlds’ largest radio telescope SKA Regional Centres • Collaborative alliance • Transparent and location agnostic interface to SRCs for users • SKA users should not care where their data products are • All SKA users should be able to access their data products, irrespective of whether their country or region hosts a regional centre
- 53. SKA Observatory SRC 1 SRC 2 SRC n SRC 3 SKA Regional Centre Alliance Users SRC Science Gateway Exploring the Universewith the worlds’ largest radio telescope SKA Regional Centres • SKA Regional Centres (SRCs) will host the SKA science archive • Provide access and distribute data products to users • Provide access to compute and storage resources • Provide analysis capabilities user support • Multiple regional SRCs, locally resourced and staffed
- 54. Conclusion SKA1 telescopes will provide transformational science • Even after re-baselining and cost- control project, SKA1 telescopes will provide unprecedented sensitivity, resolution, and survey speed (with low thermal noise) • Will provide both PI and KSP science • SKA time will be allocated mostly to KSPs, and PIs of member countries • Many KSPs fall in cosmology field • SKA time will be allocated to those who contribute to both construction and operations • An amount of time will be devoted to open-skies! Exploring the Universewith the worlds’ largest radio telescope
- 55. Thanks! Exploring the Universewith the worlds’ largest radio telescope SQUARE KILOMETRE ARRAY j.santander-vela@skatelescope.org