SZ effect and ALMA SZ effect and ALMA workshopsworkshops

Lauro MoscardiniLauro MoscardiniDipartimento di AstronomiaDipartimento di Astronomia

Università di Bologna, ItalyUniversità di Bologna, Italy

lauro.moscardini@unibo.itlauro.moscardini@unibo.it

IAS, Orsay, 7-8 April 2005OAT, Trieste, 13 April 2005

Clusters of GalaxiesClusters of Galaxiesin the Microwavesin the Microwaves

CMB+CLUSTERS Sunyaev & Zel'dovich Effect

Sunyaev & Zel'dovich Sunyaev & Zel'dovich EffectEffect

Thermal S-Z Effect

Kinetic S-Z effect

T=T s(x) yc

yc = (k BT/mec2) d

x=hp/kBT

Sunyaev & Zel'dovich Sunyaev & Zel'dovich EffectEffect

1) SZ effect depends on the projection of n along the line of sight

2) SZ effect is independent of redshift

1) Combination of SZ and X-ray observations gives important information on the gas structure ; Combination of SZ and X-ray observations provide information on the cluster Distance (estimate of H0)

2) SZ observations allow to observe (in principle) all the clusters in the universe

Goals in ParisGoals in Paris

To start discussions on what will remain to be To start discussions on what will remain to be done on the SZ effect at the beginning of 2012 done on the SZ effect at the beginning of 2012 when ALMA will be fully operationalwhen ALMA will be fully operational

To investigate the importance of observations of To investigate the importance of observations of the SZ effect at high angular resolutionthe SZ effect at high angular resolution

To define what are the key frequency bands for SZ To define what are the key frequency bands for SZ studies in the mm/submm windows, in particular, studies in the mm/submm windows, in particular, are there crucial bands which are not in the are there crucial bands which are not in the baseline project? (band 1?)baseline project? (band 1?)

Goals in TriesteGoals in Trieste

To start a discussion on what are the best To start a discussion on what are the best possible targets for ALMA observations: possible targets for ALMA observations: low- vs. high-redshift objectslow- vs. high-redshift objects

Is it possible to create a common strategy Is it possible to create a common strategy between different groups in terms of between different groups in terms of proposals? (YES)proposals? (YES)

Are the present expertizes enough to afford Are the present expertizes enough to afford the international competition? (NO)the international competition? (NO)

Requirements on observations (I)Requirements on observations (I)

UseUse Size Size (mK)(mK)

Critical issuesCritical issues

EnergeticsEnergetics 0.500.50 Absolute calibrationAbsolute calibration

Baryon countBaryon count 0.500.50 Absolute calibration; isothermal/spherical Absolute calibration; isothermal/spherical cluster; gross model cluster; gross model

Gas structureGas structure 0.500.50 Beamshape; confusionBeamshape; confusion

Mass Mass distributiondistribution

0.500.50 Absolute calibration; isothermal/spherical Absolute calibration; isothermal/spherical clustercluster

Hubble diagramHubble diagram 0.500.50 Absolute calibration; gross model; Absolute calibration; gross model; clumping; axial ratio selection biasclumping; axial ratio selection bias

BirkinshawBirkinshaw

Requirements on observations (II)Requirements on observations (II)

UseUse Size Size (mK)(mK)

Critical issuesCritical issues

Blind surveysBlind surveys 0.100.10 Gross model; confusion Gross model; confusion

Baryon fraction Baryon fraction evolutionevolution

0.100.10 Absolute calibration; isothermal/spherical Absolute calibration; isothermal/spherical cluster; gross modelcluster; gross model

CMB CMB temperaturetemperature

0.100.10 Absolute calibration; substructureAbsolute calibration; substructure

Radial velocityRadial velocity 0.050.05 Absolute calibration; gross model; Absolute calibration; gross model; bandpass calibration; velocity bandpass calibration; velocity substructuresubstructure

Status at the time of ALMA: 2005Status at the time of ALMA: 2005

Current statusCurrent status About 100 cluster detectionsAbout 100 cluster detections

– high significance (> 10high significance (> 10) detections) detections

– multi-telescope confirmationsmulti-telescope confirmations

– interferometer maps, structures usually from X-raysinterferometer maps, structures usually from X-rays

Spectral measurements still rudimentary Spectral measurements still rudimentary – no kinematic effect detectionsno kinematic effect detections

Preliminary blind and semi-blind surveysPreliminary blind and semi-blind surveys– a few detectionsa few detections

BirkinshawBirkinshaw

A 3266: A 3266: z = z = 0.060.06 VIPER +ACBARVIPER +ACBAR Images at 150, 220, Images at 150, 220,

275 GHz, 5 arcmin 275 GHz, 5 arcmin FWHMFWHM

Remove CMB to leave Remove CMB to leave thermal SZE (bottom thermal SZE (bottom right)right)

GGómez ómez et al. et al. 20032003

Status at the time of ALMA: 2010Status at the time of ALMA: 2010

About 5000 cluster detectionsAbout 5000 cluster detections– Most from Planck catalogue, low-Most from Planck catalogue, low-zz– 10% from high-resolution surveys (AMiBA, SZA, 10% from high-resolution surveys (AMiBA, SZA,

BOLOCAM, etc.)BOLOCAM, etc.) About 100 images with > 100 resolution elementsAbout 100 images with > 100 resolution elements

– Mostly interferometric, tailored arrays, 10 arcsec Mostly interferometric, tailored arrays, 10 arcsec FWHMFWHM

– Some bolometric maps, 15 arcsec FWHMSome bolometric maps, 15 arcsec FWHM About 50 integrated spectral measurements About 50 integrated spectral measurements

– Still confusion limitedStill confusion limited– Still problems with absolute calibrationStill problems with absolute calibration

Status at the time of ALMA: ALMA, Status at the time of ALMA: ALMA, 20102010

ALMA band 1 suitable for SZEALMA band 1 suitable for SZE– 1 microJy in 10 arcsec FWHM over 145 arcsec 1 microJy in 10 arcsec FWHM over 145 arcsec

primary beam in 12 hoursprimary beam in 12 hours– Cluster substructure mapping (loses largest Cluster substructure mapping (loses largest

scales)scales)– Quality of mosaics still uncertainQuality of mosaics still uncertain

Band 1 is not likely to be available in 2010Band 1 is not likely to be available in 2010 Blind surveys using ALMA band-1 not Blind surveys using ALMA band-1 not

likely – wrong angular scaleslikely – wrong angular scales

Status at the time of ALMA: X-ray Status at the time of ALMA: X-ray context: 2010context: 2010

No XMM or ChandraNo XMM or Chandra Constellation-X/XEUS not availableConstellation-X/XEUS not available

Working with archival X-ray surveysWorking with archival X-ray surveys X-ray spectra of high-z clusters of relatively poor X-ray spectra of high-z clusters of relatively poor

qualityquality

Optical/IR survey follow-up in SZE, orOptical/IR survey follow-up in SZE, or order of order of follow-ups reversed: SZE before X-ray.follow-ups reversed: SZE before X-ray.

DiscussionDiscussion

Collaboration on a single region?Collaboration on a single region? Problems with redshift!Problems with redshift! Archives for dataArchives for data Which structures you can see with ALMA:Which structures you can see with ALMA:

imaging, i.e. pressure!imaging, i.e. pressure!

remind that typical scales are from 3 to 5 arcsec remind that typical scales are from 3 to 5 arcsec and spectra are between 90-350 GHz (+)and spectra are between 90-350 GHz (+)

Conclusions (Laing)Conclusions (Laing)ALMA performance with ACA and total power:ALMA performance with ACA and total power:• emphasize compact configuration• different frequenciesSimulations of physics (see Kitayama & Kneissl)Simulations of physics (see Kitayama & Kneissl)• what might we expect to see – need S or Tb – plus spatial scales, preferably images • not just rich clusters: small scales are good, so think about cluster substructures, galaxies, groups, protoclusters, etc…Simulations of ALMA responseSimulations of ALMA response• ALMA visibility• add errors, reconstruct, work out how long

Conclusions (ctd)Conclusions (ctd)Importance of multiple frequencies:Importance of multiple frequencies:• separate tSZ, kSZ and rSZ• foreground (synchrotron, dust, …)• for cavities, need syncrothron, SZ, thermal, IC components..• absence of NEW X-ray imaging• complementary of ALMA and small interferometric arrays & bolometers: same resolution @ different frequencies

ALMA for SZ survey follow upALMA for SZ survey follow up

Conclusions (ctd)Conclusions (ctd)ALMA band 1:ALMA band 1:• ability to sample larger spatial scales: sensitivity• Band 2 less important• make a case for ALMA enhancements (NOT YET)

Lots of interesting sources for SZ:Lots of interesting sources for SZ:• substructures• cavities, bubbles, shocks, turbolence, etc• high-redshift clusters• …..

Discussion in TriesteDiscussion in Trieste

What is changing for SZ observations when What is changing for SZ observations when ALMA is used? (see e.g. talks by Testi and ALMA is used? (see e.g. talks by Testi and Andreani)Andreani)

Which are the best targets? Which are the best targets? Low-redshift clusters: properties of ICM Low-redshift clusters: properties of ICM

(see e.g. talk by Borgani)(see e.g. talk by Borgani) High-redshift clusters: global properties High-redshift clusters: global properties

(see e.g. talk by Tozzi)(see e.g. talk by Tozzi)

To be better understood

1. Refine estimates of exposure time and feasibility.

2. How ubiquitous is the turbulent ICM?

3. Go for medium-distant clusters (z=0.3-0.5) or for very local ones (z~0.1) ?

4. What else these high sensitivity SZ observations can be useful for? - Detection of shocks from diffuse accretion at Rvir? I doubt… - Detection of shocks from merging events? - Detection of ICM heating events (bubbles from AGN)? - Cosmological parameters from DA(z)? Unlike turbulence, it requires relaxed clusters.

S. BorganiS. Borgani

Turbulent ICM motions from mergingDolag et al. 2005

Reduced viscosity Normal viscosity

Detecting turbulence via ICM pressure fluctuationsSchuecker et al. 2004XMM mosaic: 16 pointings of 10 - 40 ksec exposure each.

Def. of pressure: I1/2TX

The physics of the ICM (and the nature of the non-gravitational energy budget) can be studied in low-z, bright clusters where the X-ray information dominates.

Why an SZ follow up of Why an SZ follow up of high-z,high-z, X-ray clusters? X-ray clusters?X-ray information is rapidly lost at high z:low SB in external region (difficult to recover the T Gradient), lost of information on T (and P) structure in the inner region due to low S/N redshifting of the spectral band. SZ observations can help in recovering SZ observations can help in recovering the information lost from the X-ray band.the information lost from the X-ray band.

P. TozziP. Tozzi

~60 Clusters with L, ngas

,T, Z @ z>0.3

Cosmological impact of SZ follow-up of X-ray, high-z clusters:

Understanding the P (T) structure of the ICM in the inner regions

The impact of massive merger on the thermodynamics structure of the ICM (increasing relevance at high-z)

Improve cosmological tests like baryonic fraction affected by T gradients

Understanding the nature of self-similarity break (AGN heating, SN heating)?

...