Z-Spec results - PowerPoint Presentation

Slide1

Z-Spec resultsSlide2

April 2008

7.9 hours

half

t~0.5, half t~0.15

Molecular gas reservoirs probed with CO, H

2OSlide3

Wideband Spectroscopy Probes the Cosmic History of Star Formation

HeRMES Survey

Bright (lensed) sources identified at 250, 350, 500

mm.

HSLS 1

Wang, Barger and Cowie, 2009July 2, 2012

3

BLISS for SPICA, M. Bradford et al.

Direct Z-Spec redshift with CO lines in the mm: z=2.95

Near-IR Imaging.

Which / Where is counterpart ??

Near-IR Imaging.

Kp-band Keck AO

CO 5-4 PdB

Z-Spec redshift enables PdB tuning for image of CO 5-4

Lens modeling w/ K, CO:

m

=10, Gavazzi+ 2011

Z-Spec / CSO

K. Scott + 2011Slide4

X-Spec:

A

Multi-Object Wideband Spectrograph for CCAT

Matt Bradford + X-Spec teamSlide5

Growth of Cosmic Star-Formation

SF history: Hopkins and

Beacom

, 2006We would like to chart the onset and early growth of star formation in the epoch prior to

z=4 (the first 1.5 Billion years) ?e.g.

was this dominated by massive galaxies or small ones? How much does dusty SF contribute?z>4 has large uncertainties and all data on this epoch comes from rest-frame UV / optical surveys (Lyman break sources)

Require redshift-resolved far-IR / submm luminosity functions to complement UV-based studies.Slide6

Galaxy evolution in the first 1.5 billion years

LF

at early times completely unconstrained. Extrapolations from UV fluxes to total luminosity very uncertain.

Redshifts estimated via far-IR / submm colors have large intrinsic uncertainty.Want ~ 10k spectroscopic redshifts in order to provide well-sampled luminosity functions from z=10 to z=4 in

Dz/(1+z)=5% bins Can’t do with ALMA.

z=4.4z

=7.3Galaxy luminosity

function, converted to C+ ‘line counts’Slide7

X-Spec Spectroscopic

survey goals

Measure high

-z (z>4) luminosity functions w/ C+ by following up ‘red’ submm / mm sources: ~8 redshift x

~8 luminosity bins reaching below the knee, 100 sources per bin --> 1000s of redshifts.

Also provides independent study of growth of structure, require depth which gives ~100 sources per square degree (per redshift bin) over >20 square degrees.C+ detections also provide interstellar gas properties (mass, temperature, UV field strength)Measure

molecular gas content in galaxies through the bulk of SF history (z=4 to 1) with the CO rotational ladder, both

individual sources and

stacking

on known

(e.g. optical) redshifts.

Requires

30

-300 beams on the sky with full coverage of low-frequency atmospheric windows.

ALMA (8GHz) requires 10-20 years.

100-object X-Spec CCAT requires ~3 years.Slide8

CCAT Spectroscopic Sensitivity

CCAT – X-Spec

vs

ALMA for line surveysALMA is ~13 times more sensitive than CCAT, per CCAT spectrometer beam (CCAT single pol)ALMA: 8 GHz BW, requires ~30 tunings to cover Band 1 + Band 2, but assume

only 8 tunings to measure

z.A ~30

-beam X-Spec is a factor of 1.3 times faster

than

ALMA

(or

15 beams

x

2

polarizations).

A ~300-beam

X-Spec is 13 times faster than ALMA (or 150 beams x

2 polarizations).We will field a 30-300 (beam x

Npol) system for first light with technology that can scale to produce an instrument with thousands of beams in the 2020 decade.

L = 2 x 10

12

Detect L ~ 3 x 10

11

L

sun

galaxy in 10

hrs (3

σ

)

S. Hailey-

Dunsheath

SNR, 20hSlide9

Implementation of X-Spec

Core technology is new

superconducting

on-chip filter-bank spectrometer SuperSpec with on-board Kinetic Inductance Detector (KID) array: 500-channel R=700 chip covers Band 1 or Band 2, each is a few cm2 in size

Low-cost microfabrication -> instrument cost not dominated by detectors themselves.

Each chip (each spectrometer beam) coupled with a feedhorn or planar antenna. At first light we will deploy 30-300 beams, depending primarily on the cost of KID readouts. Studying 2 system architectures with downselect during design phase:1) Direct multi-pixel spectral imager scans the sky as per bolometric cameras

Single-band array. Eventual architecture of choice as pixel count increases2) Incorporate steered front end for each spectrometer with an articulated quasioptical

relay to couple to galaxy with a known position.

Optimal in the limit of small number of pixels, since source density on the sky is 1e-2 to 1e-3 per beam. Sensible if steering system is less expensive than ~10-100 spectrometer chips + readouts.

Use dual-band, dual

pol

architecture (4 chips per feed unit)Slide10

SuperSpec

:

New

On-Chip Spectrometer TechnologyCaltech & JPLC.M. BradfordG. ChattopadhyayP. DayS. Hailey-DunsheathA. KovacsC. McKenney

R. O’Brient

S. PadinT. ReckE. ShirokoffL. Swenson

J. Zmuidzinas

Cardiff University

P. Barry

S. Doyle

Arizona State U.

P.

Mauskopf

Complutense

U. of Madrid

N. Llombart

U. ArizonaD.P. Marrone

(boldface => postdoctoral researcher)Slide11

SuperSpec

A revolutionary

on-chip, mm-wave

f

ilter

-

bank spectrometer using kinetic inductance detectors (KIDs)

Simulated response for various channel spacing

Feedline

and 2 full readout channels

Mm-wave radiation couples

to a bank of half-wave

resonant filters,

deposits power in the

MKID inductor

KID inductor

KID capacitor

mm resonator (filter)

mm

feedline

Signal coupled via a feedhorn propagates on a superconducting transmission line.

A suite of half-wave resonators, one for each frequency bin, is coupled to the main

feedline

and to a direct detector (a KID).

For CCAT X-Spec, we will have

~500

channels from

195-305 GHz in a chip of size is 2-4 cm

2

, using a single RF

single readout

line. Another chip with separate horn / antenna + readout covers 320-470 GHz.Slide12

7 mm

SuperSpec

first 80-channel test device

Yield in KID resonators nearly perfect! (now using 100-250 MHz

KIDs

)Feedhorn-coupled optical measurements coming soon.Erik

Shirokoff, chip designSlide13

SuperSpec

first 80-channel test device

Yield in KID resonators nearly perfect! (now using 100-250 MHz

KIDs)Feedhorn-coupled optical measurements coming soon.

KID coupling capacitors

mm-wave feedline (niobium, traveling horizontally)

KID resonator capacitors

(titanium nitride,

interdigitated

)

m

m-wave half-wave resonator (U-shape, niobium)

m

m-wave absorber = meandered KID inductor (titanium nitride)

Erik

Shirokoff

, chip design