outline - university of arizonagbesla/astr_520_files/gurtina... · the origin of candels • hst...

Outline• History

• Science motivation

• Survey description

• Major science results

The origin of CANDELS• HST Multi-cycle treasury programs, call for proposal

2009

• Up to 750 orbits available per program to address science questions that cannot be tackled through standard time allocations.

• 39 Proposals were submitted, requesting total of 26,801 orbits (oversubscription 12:1)

• 3.5 proposals were accepted (3.5???)

The origin of CANDELS• Two teams submitted compelling proposals to do

deep Near-IR imaging (WFC3) in well studied deep fields

• PI: Sandy Faber (UCSC) with DEEP + DEEP2 survey teams

• request: 907 orbits, shallow imaging of AEGIS, COSMOS, UDS, deep imaging of small chunks of the GOODS fields

• PI: Harry Ferguson (STScI) with GOODS survey team

• request: 786 orbits, deep imaging of GOODS fields, spectroscopic followup of SN 1a candidates

The origin of CANDELS• TAC accepted both Faber and Ferguson proposals


PI: Faber(DEEP/AEGIS

Team)

PI: Ferguson(GOODS

Survey Team)+

=Joint program, 902 HST orbits!


PI: Faber(DEEP/AEGIS

Team)

PI: Ferguson(GOODS

Survey Team)+

=

Joint program, TAC mandated this new team execute best

features from both proposals902 HST orbits!

The merged team

• Total: 94 co-Is, including students/postdocs = 175 team members from 45 institutes in 12 countries

CANDELS meeting, Santa Cruz 2012

• Total: 94 co-Is, including students/postdocs = 175 team members from 45 institutes in 12 countries

The merged team

CANDELS meeting, Santa Cruz 2012 Former and current Tucsonans!

•1 < z < 3

Multi-purpose survey, many goals in different fields from the same dataset

S. Finkelstein

Exposure Strategy

“Wedding cake” strategy: three layers of J+H

WIDE: 2 orbit depth over ~0.2 sq deg

DEEP: 8 orbit depth over ~0.04 sq deg

UDFs: 50-100 orbit depth over ~0.004 sq deg

Fig courtesy H. Ferguson

Science Goals/Motivation

•

z > 6

1 < z < 3

Improve constraints on bright end of galaxy luminosity fn Constraint UV luminosity density at the end of reionization

z~7 z~8

Near-IR: probes older stellar populations at z>1 (optical imaging strongly biased to SF regions)

+Study stellar mass buildup+Study relationship between galactic structure, star-formation history, mass assembly+Mass-limited census of galaxies M > 2x10^9+Galactic sub-structures, bulge formation

Existing space and

ground

Photometry gains

Fig courtesy H. Ferguson

Photometry gains

New WFC3

+ Continue studying supernova cosmology to z > 1.5

+ Is there evidence for evolution in Type 1a Supernovae? Are they still good distance indicators?

+ Can SN rates say something about the progenitors?

• WFC3 (Near-IR) observations with ACS in parallel

•1 < z < 3

Multi-purpose survey, many goals in different fields from the same dataset

Near-IR: probes older stellar populations at z>1 (optical imaging strongly biased to SF regions)

Galaxies at z~2: Quenched galaxies spheroidal and compactSFGs have diverse morphology

Selected results from CANDELS

Lee et al. 2013


• Sersic index (measure of steepness of light profile) seems to be the best predictor of if a galaxy is quenched. Quenching at z~2 and morphology are linked

Bell et al. 2012

Selected results from CANDELS Cassata et al. 2013

• Number density evolution of quenched galaxies

• First quenched galaxies nearly all compact

• Over time the compact quenched disappear...


Fig: J. Lotz• Why does quenching happen?

Merger driven AGN scenario?


Kocevski et al. 2012

• No significant trend between AGN and merger signatures. AGN exist in both spheroids and disks

x-ray selected AGN


Rodney et al. 2014

Constraining the progenitor population of Type 1a SN: low fraction of “prompt” SN (i.e. short timescale to explosion - Single Degenerate model)

CANDELS data favors the double degenerate or (longer timescale) models

CANDELS+CLASH SNe

outline - university of arizonagbesla/astr_520_files/gurtina... · the origin of candels • hst...

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