-
J. Dunkley,
E. Calabrese,
J. Sievers,
G. E. Addison,
N. Battaglia, E. S. Battistelli,
J. R. Bond,
S. Das,
M. J. Devlin,
R. Dunner, [......],
M. Niemack,
M. R. Nolta,
L. A. Page,
B. Partridge,
N. Sehgal,
D. N. Spergel,
S. T. Staggs,
E. R. Switzer,
H. Trac,
E. Wollack
[show abstract]
[hide abstract]
ABSTRACT: The Atacama Cosmology Telescope has measured the angular power spectra of
microwave fluctuations to arcminute scales at frequencies of 148 and 218 GHz,
from three seasons of data. At small scales the fluctuations in the primordial
Cosmic Microwave Background (CMB) become increasingly obscured by extragalactic
foregounds and secondary CMB signals. We present results from a nine-parameter
model describing these secondary effects, including the thermal and kinematic
Sunyaev-Zel'dovich (tSZ and kSZ) power; the clustered and Poisson-like power
from Cosmic Infrared Background (CIB) sources, and their frequency scaling; the
tSZ-CIB correlation coefficient; the extragalactic radio source power; and
thermal dust emission from Galactic cirrus in two different regions of the sky.
In order to extract cosmological parameters, we describe a likelihood function
for the ACT data, fitting this model to the multi-frequency spectra in the
multipole range 500<ell<10000. We extend the likelihood to include spectra from
the South Pole Telescope at frequencies of 95, 150, and 220 GHz. Accounting for
different radio source levels and Galactic cirrus emission, the same model
provides an excellent fit to both datasets simultaneously, with chi2/dof=
675/697 for ACT, and 96/107 for SPT. We then use the multi-frequency likelihood
to estimate the CMB power spectrum from ACT in bandpowers, marginalizing over
the secondary parameters. This provides a simplified `CMB-only' likelihood in
the range 500<ell<3500 for use in cosmological parameter estimation.
01/2013;
-
R Dünner,
M Hasselfield,
T ~A Marriage,
J Sievers,
V Acquaviva,
G ~E Addison,
P ~A ~R Ade,
P Aguirre,
M Amiri,
J ~W Appel, [......],
S ~T Staggs,
D ~S Swetz,
E ~R Switzer,
R Thornton,
H Trac,
C Tucker,
R Warne,
G Wilson,
E Wollack,
Y Zhao
apj. 01/2013; 762:10.
-
D. S. Swetz,
P. A. R. Ade,
M. Amiri,
J. W. Appel, E. S. Battistelli,
B. Burger,
J. Chervenak,
M. J. Devlin,
S. R. Dicker,
W. B. Doriese, [......],
M. R. Nolta,
L. A. Page,
L. Parker,
S. T. Staggs,
O. Stryzak,
E. R. Switzer,
R. Thornton,
C. Tucker,
E. Wollack,
and Y. Zhao
[show abstract]
[hide abstract]
ABSTRACT: The Atacama Cosmology Telescope was designed to measure small-scale anisotropies in the cosmic microwave background and detect galaxy clusters through the Sunyaev-Zel'dovich effect. The instrument is located on Cerro Toco in the Atacama Desert, at an altitude of 5190 m. A 6 m off-axis Gregorian telescope feeds a new type of cryogenic receiver, the Millimeter Bolometer Array Camera. The receiver features three 1000-element arrays of transition-edge sensor bolometers for observations at 148 GHz, 218 GHz, and 277 GHz. Each detector array is fed by free space millimeter-wave optics. Each frequency band has a field of view of approximately 22' × 26'. The telescope was commissioned in 2007 and has completed its third year of operations. We discuss the major components of the telescope, camera, and related systems, and summarize the instrument performance.
The Astrophysical Journal Supplement Series 05/2011; 194(2):41. · 13.46 Impact Factor
-
A. D. Hincks,
V. Acquaviva,
P. A. R. Ade,
P. Aguirre,
M. Amiri,
J. W. Appel,
L. F. Barrientos, E. S. Battistelli,
J. R. Bond,
B. Brown, [......],
D. S. Swetz,
E. R. Switzer,
R. Thornton,
H. Trac,
C. Tucker,
L. Verde,
R. Warne,
G. Wilson,
E. Wollack,
and Y. Zhao
[show abstract]
[hide abstract]
ABSTRACT: The Atacama Cosmology Telescope (ACT) is currently observing the cosmic microwave background with arcminute resolution at 148 GHz, 218 GHz, and 277 GHz. In this paper, we present ACT's first results. Data have been analyzed using a maximum-likelihood map-making method which uses B-splines to model and remove the atmospheric signal. It has been used to make high-precision beam maps from which we determine the experiment's window functions. This beam information directly impacts all subsequent analyses of the data. We also used the method to map a sample of galaxy clusters via the Sunyaev-Zel'dovich (SZ) effect and show five clusters previously detected with X-ray or SZ observations. We provide integrated Compton-y measurements for each cluster. Of particular interest is our detection of the z = 0.44 component of A3128 and our current non-detection of the low-redshift part, providing strong evidence that the further cluster is more massive as suggested by X-ray measurements. This is a compelling example of the redshift-independent mass selection of the SZ effect.
The Astrophysical Journal Supplement Series 12/2010; 191(2):423. · 13.46 Impact Factor
-
T. A. Marriage,
V. Acquaviva,
P. A. R. Ade,
P. Aguirre,
M. Amiri,
J. W. Appel,
L. F. Barrientos, E. S. Battistelli,
J. R. Bond,
B Brown, [......],
S. T. Staggs,
D. S. Swetz,
E. R. Switzer,
R. Thornton,
H. Trac,
C. Tucker,
R. Warne,
G Wilson,
E. Wollack,
Y Zhao
[show abstract]
[hide abstract]
ABSTRACT: We report on twenty-three clusters detected blindly as Sunyaev-Zel'dovich
(SZ) decrements in a 148 GHz, 455 square-degree map of the southern sky made
with data from the Atacama Cosmology Telescope 2008 observing season. All SZ
detections announced in this work have confirmed optical counterparts. Ten of
the clusters are new discoveries. One newly discovered cluster, ACT-CL
J0102-4915, with a redshift of 0.75 (photometric), has an SZ decrement
comparable to the most massive systems at lower redshifts. Simulations of the
cluster recovery method reproduce the sample purity measured by optical
follow-up. In particular, for clusters detected with a signal-to-noise ratio
greater than six, simulations are consistent with optical follow-up that
demonstrated this subsample is 100% pure. The simulations further imply that
the total sample is 80% complete for clusters with mass in excess of 6x10^14
solar masses referenced to the cluster volume characterized by five hundred
times the critical density. The Compton y -- X-ray luminosity mass comparison
for the eleven best detected clusters visually agrees with both self-similar
and non-adiabatic, simulation-derived scaling laws.
10/2010;
-
J. Dunkley,
R. Hlozek,
J. Sievers,
V. Acquaviva,
P. A. R. Ade,
P. Aguirre,
M. Amiri,
J. W. Appel,
L. F. Barrientos, E. S. Battistelli, [......],
D. N. Spergel,
S. T. Staggs,
D. S. Swetz,
E. R. Switzer,
R. Thornton,
H. Trac,
C. Tucker,
R. Warne,
E. Wollack,
Y Zhao
[show abstract]
[hide abstract]
ABSTRACT: We present cosmological parameters derived from the angular power spectrum of the cosmic microwave background (CMB) radiation observed at 148 GHz and 218 GHz over 296 deg^2 with the Atacama Cosmology Telescope (ACT) during its 2008 season. ACT measures fluctuations at scales 500<l<10000. We fit a model for the lensed CMB, Sunyaev-Zel'dovich (SZ), and foreground contribution to the 148 GHz and 218 GHz power spectra, including thermal and kinetic SZ, Poisson power from radio and infrared point sources, and clustered power from infrared point sources. The power from thermal and kinetic SZ at 148 GHz is estimated to be B_3000 = 6.8+-2.9 uK^2, where B_l=l(l+1)C_l/2pi. We estimate primary cosmological parameters from the 148 GHz spectrum, marginalizing over SZ and source power. The LCDM cosmological model is a good fit to the data, and LCDM parameters estimated from ACT+WMAP are consistent with the 7-year WMAP limits, with scale invariant n_s = 1 excluded at 99.7% CL (3sigma). A model with no CMB lensing is disfavored at 2.8sigma. By measuring the third to seventh acoustic peaks, and probing the Silk damping regime, the ACT data improve limits on cosmological parameters that affect the small-scale CMB power. The ACT data combined with WMAP give a 6sigma detection of primordial helium, with Y_P = 0.313+-0.044, and a 4sigma detection of relativistic species, assumed to be neutrinos, with Neff = 5.3+-1.3 (4.6+-0.8 with BAO+H0 data). From the CMB alone the running of the spectral index is constrained to be dn/dlnk = -0.034 +- 0.018, the limit on the tensor-to-scalar ratio is r<0.25 (95% CL), and the possible contribution of Nambu cosmic strings to the power spectrum is constrained to string tension Gmu<1.6 \times 10^-7 (95% CL). Comment: 20 pages, 13 figures. Submitted to ApJ. This paper is a companion to Hajian et al. (2010) and Das et al. (2010)
09/2010;
-
T. A. Marriage,
J. B. Juin,
Y T Lin,
D. Marsden,
M. R. Nolta,
B. Partridge,
P. A. R. Ade,
P. Aguirre,
M. Amiri,
J. W. Appel, [......],
S. T. Staggs,
D. S. Swetz,
E. R. Switzer,
R. Thornton,
H. Trac,
C. Tucker,
R. Warne,
G Wilson,
E. Wollack,
Y Zhao
[show abstract]
[hide abstract]
ABSTRACT: We report on extragalactic sources detected in a 455 square-degree map of the
southern sky made with data at a frequency of 148 GHz from the Atacama
Cosmology Telescope 2008 observing season. We provide a catalog of 157 sources
with flux densities spanning two orders of magnitude: from 15 to 1500 mJy.
Comparison to other catalogs shows that 98% of the ACT detections correspond to
sources detected at lower radio frequencies. Three of the sources appear to be
associated with the brightest cluster galaxies of low redshift X-ray selected
galaxy clusters. Estimates of the radio to mm-wave spectral indices and
differential counts of the sources further bolster the hypothesis that they are
nearly all radio sources, and that their emission is not dominated by
re-emission from warm dust. In a bright (>50 mJy) 148 GHz-selected sample with
complete cross-identifications from the Australia Telescope 20 GHz survey, we
observe an average steepening of the spectra between 5, 20, and 148 GHz with
median spectral indices of $\alpha_{\rm 5-20} = -0.07 \pm 0.06$, $\alpha_{\rm
20-148} = -0.39 \pm0.04$, and $\alpha_{\rm 5-148} = -0.20 \pm 0.03$. When the
measured spectral indices are taken into account, the 148 GHz differential
source counts are consistent with previous measurements at 30 GHz in the
context of a source count model dominated by radio sources. Extrapolating with
an appropriately rescaled model for the radio source counts, the Poisson
contribution to the spatial power spectrum from synchrotron-dominated sources
with flux density less than 20 mJy is $C^{\rm Sync} = (2.8 \pm 0.3) \times
10^{-6} \micro\kelvin^2$.
J. Sievers D. N. Spergel E. R. Switzer. 07/2010; 192410510101910101510291(13).
-
D. S. Swetz,
P. A. R. Ade,
M. Amiri,
J. W. Appel, E. S. Battistelli,
B. Burger,
J. Chervenak,
M. J. Devlin,
S. R. Dicker,
W. B. Doriese, [......],
M. R. Nolta,
L. A. Page,
L. Parker,
S. T. Staggs,
O. Stryzak,
E. R. Switzer,
R. Thornton,
C. Tucker,
E. Wollack,
Y Zhao
[show abstract]
[hide abstract]
ABSTRACT: The Atacama Cosmology Telescope was designed to measure small-scale
anisotropies in the Cosmic Microwave Background and detect galaxy clusters
through the Sunyaev-Zel'dovich effect. The instrument is located on Cerro Toco
in the Atacama Desert, at an altitude of 5190 meters. A six-meter off-axis
Gregorian telescope feeds a new type of cryogenic receiver, the Millimeter
Bolometer Array Camera. The receiver features three 1000-element arrays of
transition-edge sensor bolometers for observations at 148 GHz, 218 GHz, and 277
GHz. Each detector array is fed by free space mm-wave optics. Each frequency
band has a field of view of approximately 22' x 26'. The telescope was
commissioned in 2007 and has completed its third year of operations. We discuss
the major components of the telescope, camera, and related systems, and
summarize the instrument performance.
07/2010;
-
J. W. Fowler,
V. Acquaviva,
P. A. R. Ade,
P. Aguirre,
M. Amiri,
J. W. Appel,
L. F. Barrientos, E. S. Battistelli,
J. R. Bond,
B Brown, [......],
E. R. Switzer,
R. Thornton,
H. Trac,
C. Tucker,
L. Verde,
R. Warne,
G Wilson,
E. Wollack,
Y Zhao,
the ACT Collaboration
[show abstract]
[hide abstract]
ABSTRACT: We present a measurement of the angular power spectrum of the cosmic microwave background (CMB) radiation observed at 148 GHz. The measurement uses maps with 1.4' angular resolution made with data from the Atacama Cosmology Telescope (ACT). The observations cover 228 square degrees of the southern sky, in a 4.2-degree-wide strip centered on declination 53 degrees South. The CMB at arcminute angular scales is particularly sensitive to the Silk damping scale, to the Sunyaev-Zel'dovich (SZ) effect from galaxy clusters, and to emission by radio sources and dusty galaxies. After masking the 108 brightest point sources in our maps, we estimate the power spectrum between 600 < \ell < 8000 using the adaptive multi-taper method to minimize spectral leakage and maximize use of the full data set. Our absolute calibration is based on observations of Uranus. To verify the calibration and test the fidelity of our map at large angular scales, we cross-correlate the ACT map to the WMAP map and recover the WMAP power spectrum from 250 < ell < 1150. The power beyond the Silk damping tail of the CMB is consistent with models of the emission from point sources. We quantify the contribution of SZ clusters to the power spectrum by fitting to a model normalized at sigma8 = 0.8. We constrain the model's amplitude ASZ < 1.63 (95% CL). If interpreted as a measurement of sigma8, this implies sigma8^SZ < 0.86 (95% CL) given our SZ model. A fit of ACT and WMAP five-year data jointly to a 6-parameter LCDM model plus terms for point sources and the SZ effect is consistent with these results. Comment: 15 pages, 8 figures. Accepted for publication in ApJ
01/2010;
-
[show abstract]
[hide abstract]
ABSTRACT: We have determined the CMB temperature, $T(z)$, at redshifts in the range 0.023-0.546, from multi-frequency measurements of the S-Z effect towards 13 clusters. We extract the parameter $\alpha$ in the redshift scaling $T(z)=T_{0}(1+z)^{1-\alpha}$, which contrasts the prediction of the standard model ($\alpha=0$) with that in non-adiabatic evolution conjectured in some alternative cosmological models. The statistical analysis is based on two main approaches: using ratios of the S-Z intensity change, $\Delta I$, thus taking advantage of the weak dependence of the ratios on IC gas properties, and using directly the $\Delta I$ measurements. In the former method dependence on the Thomson optical depth and gas temperature is only second order in these quantities. In the second method we marginalize over these quantities which appear to first order in the intensity change. The marginalization itself is done in two ways - by direct integrations, and by a Monte Carlo Markov Chain approach. Employing these different methods we obtain two sets of results that are consistent with $\alpha=0$, in agreement with the prediction of the standard model. Comment: Accepted for publication in ApJ
09/2009;
-
I. Flores-Cacho,
J. A. Rubiño-Martín,
G. Luzzi,
R. Rebolo,
M. De Petris,
G. Yepes,
L. Lamagna,
S. De Gregori, E. S. Battistelli,
R. Coratella,
S. Gottlöber
[show abstract]
[hide abstract]
ABSTRACT: [Abridged] We study the thermal and kinetic Sunyaev-Zel'dovich (SZ) effect associated with superclusters of galaxies using the MareNostrum Universe SPH simulation. We consider superclusters similar to the Corona Borealis Supercluster (CrB-SC). This paper is motivated by the detection at 33GHz of a strong temperature decrement in the CMB towards the core of this supercluster. Multifrequency observations with VSA and MITO suggest the existence of a thermal SZ effect component in the spectrum of this cold spot, which would account for roughly 25% of the total observed decrement. We identify nine regions containing superclusters similar to CrB-SC, obtain the associated SZ maps and calculate the probability of finding such SZ signals arising from hot gas within the supercluster. Our results show that WHIM produces a thermal SZ effect much smaller than the observed value. Neither can summing the contribution of small clusters and galaxy groups in the region explain the amplitude of the SZ signal. When we take into account the actual posterior distribution from the observations, the probability that WHIM can cause a thermal SZ signal like the one observed is <1%, rising up to a 3.2% when the contribution of small clusters and galaxy groups is included. If the simulations provide a suitable description of the gas physics, then we conclude that the thermal SZ component of the CrB spot most probably arises from an unknown galaxy cluster along the line of sight. The simulations also show that the kinetic SZ signal associated with the supercluster cannot provide an explanation for the remaining 75% of the observed cold spot in CrB. Comment: Accepted for publication in MNRAS. 14 pages, 9 figures
08/2009;
-
E. S. Battistelli,
M. De Petris,
L. Lamagna,
R. A. Watson,
R. Rebolo,
F. Melchiorri,
R. Génova-Santos,
G. Luzzi,
S. De Gregori,
J. A. Rubiño-Martin,
R. D. Davies,
R. J. Davis,
K. Grainge,
M. P. Hobson,
R. D. E. Saunders,
and P. F. Scott
[show abstract]
[hide abstract]
ABSTRACT: We have observed the Corona Borealis supercluster with the Millimeter and Infrared Testa Grigia Observatory (MITO), located in the Italian Alps, at 143, 214, 272, and 353 GHz. We present a description of the measurements, data analysis, and results of the observations together with a comparison with observations performed at 33 GHz with the Very Small Array (VSA) interferometer situated at the Teide Observatory (Tenerife, Spain). Observations have been made in the direction of the supercluster toward a cosmic microwave background (CMB) cold spot previously detected in a VSA temperature map. Observational strategy and data analysis are described in detail, explaining the procedures used to disentangle primary and secondary anisotropies in the resulting maps. From a first level of data analysis, we find evidence in MITO data of primary anisotropy but still with room for the presence of secondary anisotropy, especially when VSA results are included. With a second level of data analysis using map making and the maximum entropy method, we claim a weak detection of a faint signal compatible with a SZ effect, characterized at most by a Comptonization parameter y = (7.8) × 10-6 68% CL. The low level of confidence in the presence of a SZ signal invites us to study this sky region with higher sensitivity and angular resolution experiments such as the already-planned upgraded versions of VSA and MITO.
The Astrophysical Journal 12/2008; 645(2):826. · 6.02 Impact Factor
-
E. S. Battistelli,
M. De Petris,
L. Lamagna,
G. Luzzi,
R. Maoli,
A. Melchiorri,
F. Melchiorri,
A. Orlando,
E. Palladino,
G. Savini,
Y. Rephaeli,
M. Shimon,
M. Signore,
and S. Colafrancesco
[show abstract]
[hide abstract]
ABSTRACT: The Sunyaev-Zel'dovich (SZ) effect was previously measured in the Coma Cluster by the Owens Valley Radio Observatory and Millimeter and IR Testa Grigia Observatory experiments and recently also with the W ilkinson Microwave Anisotropy Probe satellite. We assess the consistency of these results and their implications on the feasibility of high-frequency SZ work with ground-based telescopes. The unique data set from the combined measurements at six frequency bands is jointly analyzed, resulting in a best-fit value for the Thomson optical depth at the cluster center, τ0 = (5.35 ± 0.67) × 10-3. The combined X-ray and SZ determined properties of the gas are used to determine the Hubble constant. For isothermal gas with a β density profile we derive H0 = 84 ± 26 km (s Mpc)-1; the (1 σ) error includes only observational SZ and X-ray uncertainties.
The Astrophysical Journal 12/2008; 598(2):L75. · 6.02 Impact Factor
-
C. J. MacTavish,
P. A. R. Ade, E. S. Battistelli,
S. Benton,
R. Bihary,
J. J. Bock,
J. R. Bond,
J. Brevik,
S. Bryan,
C. R. Contaldi, [......],
T. E. Montroy,
C. B. Netterfield,
D. Riley,
J. E. Ruhl,
M. Runyan,
A. Trangsrud,
C. Tucker,
A. Turner,
M. Viero,
and D. Wiebe
[show abstract]
[hide abstract]
ABSTRACT: Spider is a long-duration, balloon-borne polarimeter designed to measure large-scale cosmic microwave background (CMB) polarization with very high sensitivity and control of systematics. The instrument will map over half the sky with degree angular resolution in the I, Q, and U Stokes parameters in four frequency bands from 96 to 275 GHz. Spider's ultimate goal is to detect the primordial gravity-wave signal imprinted on the CMB B-mode polarization. One of the challenges in achieving this goal is the minimization of the contamination of B-modes by systematic effects. This paper explores a number of instrument systematics and observing strategies in order to optimize B-mode sensitivity. This is done by injecting realistic-amplitude, time-varying systematics into a set of simulated time streams. Tests of the impact of detector noise characteristics, pointing jitter, payload pendulations, polarization angle offsets, beam systematics, and receiver gain drifts are shown. Spider's default observing strategy is to spin continuously in azimuth, with polarization modulation achieved by either a rapidly spinning half-wave plate or a rapidly spinning gondola and a slowly stepped half-wave plate. Although the latter is more susceptible to systematics, the results shown here indicate that either mode of operation can be used by Spider.
The Astrophysical Journal 12/2008; 689(2):655. · 6.02 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We have deduced the cosmic microwave background temperature in the Coma Cluster (A1656, z = 0.0231) and in A2163 (z = 0.203) from spectral measurements of the Sunyaev-Zeldovich (SZ) effect over four passbands at radio and microwave frequencies. The resulting temperatures at these redshifts are TComa = 2.789 K and TA2163 = 3.377 K, respectively. These values confirm the expected relation T(z) = T0(1 + z), where T0 = 2.725 ± 0.002 K is the value measured by the COBE Far Infrared Absolute Spectrometer experiment. Alternative scaling relations that are conjectured in nonstandard cosmologies can be constrained by the data; for example, if T(z) = T0(1 + z)1-a or T(z) = T0[1 + (1 + d)z], then a = -0.16 and d = 0.17 ± 0.36 (at 95% confidence). We briefly discuss future prospects for more precise SZ measurements of T(z) at higher redshifts.
The Astrophysical Journal 12/2008; 580(2):L101. · 6.02 Impact Factor
-
E. S. Battistelli,
M. Amiri,
B. Burger,
M. J. Devlin,
S. R. Dicker,
W. B. Doriese,
R. Dünner,
R. P. Fisher,
J. W. Fowler,
M. Halpern, [......],
M. Limon,
T. A. Marriage,
M. D. Niemack,
L. Page,
C. D. Reintsema,
S. T. Staggs,
D. S. Swetz,
E. R. Switzer,
R. J. Thornton,
Y. Zhao
[show abstract]
[hide abstract]
ABSTRACT: The Atacama Cosmology Telescope observes the Cosmic Microwave Background with arcminute resolution
from the Atacama desert in Chile. For the first observing season one array of 32 x 32 Transition Edge
Sensor (TES) bolometers was installed in the primary ACT receiver, the Millimeter Bolometer Array Camera
(MBAC). In the next season, three independent arrays working at 145, 220 and 280 GHz will be installed in
MBAC. The three bolometer arrays are each coupled to a time-domain multiplexer developed at the National
Institute of Standard and Technology, Boulder, which comprises three stages of superconducting quantum
interference devices (SQUIDs). The arrays and multiplexers are read-out and controlled by the Multi Channel
Electronics (MCE) developed at the University of British Columbia, Vancouver.
A number of experiments plan to use the MCE as read-out electronics and thus the procedure for tuning the
three stage SQUID system is of general interest. Here we describe the automated array tuning procedures and
algorithms we have developed. During array tuning, the SQUIDs are biased near their critical currents. SQUID
feedback currents and lock points are selected to maximize linearity, dynamic range, and gain of the SQUID
response curves. Our automatic array characterization optimizes the tuning of all three stages of SQUIDs by
selecting over 1100 parameters per array during the first observing season and over 2100 parameters during the
second observing season. We discuss the timing, performance, and reliability of this array tuning procedure
as well as planned and recently implemented improvements.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
08/2008;
-
D. S. Swetz,
P. A. R. Ade,
C. Allen,
M. Amiri,
J. W. Appel, E. S. Battistelli,
B. Burger,
J. A. Chervenak,
A. J. Dahlen,
S. Das, [......],
N. Sehgal,
J. L. Sievers,
D. N. Spergel,
S. T. Staggs,
O. R. Stryzak,
E. R. Switzer,
R. J. Thornton,
C. Tucker,
E. J. Wollack,
Y. Zhao
[show abstract]
[hide abstract]
ABSTRACT: The Millimeter Bolometer Array Camera (MBAC) was commissioned in the fall of 2007 on the new 6-meter
Atacama Cosmology Telescope (ACT). The MBAC on the ACT will map the temperature anisotropies of the
Cosmic Microwave Background (CMB) with arc-minute resolution. For this first observing season, the MBAC
contained a diffraction-limited, 32 by 32 element, focal plane array of Transition Edge Sensor (TES) bolometers
for observations at 145 GHz. This array was coupled to the telescope with a series of cold, refractive, reimaging
optics. To meet the performance specifications, the MBAC employs four stages of cooling using closed-cycle
3He/4He sorption fridge systems in combination with pulse tube coolers. In this paper we present the design of
the instrument and discuss its performance during the first observing season. Finally, we report on the status
of the MBAC for the 2008 observing season, when the instrument will be upgraded to a total of three separate
1024-element arrays at 145 GHz, 220 GHz and 280 GHz.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
08/2008;
-
E ~S Battistelli,
M Amiri,
B Burger,
M ~J Devlin,
S ~R Dicker,
W ~B Doriese,
R Dünner,
R ~P Fisher,
J ~W Fowler,
M Halpern, [......],
M Limon,
T ~A Marriage,
M ~D Niemack,
L Page,
C ~D Reintsema,
S ~T Staggs,
D ~S Swetz,
E ~R Switzer,
R ~J Thornton,
Y Zhao
Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series; 08/2008
-
A ~D Hincks,
P ~A ~R Ade,
C Allen,
M Amiri,
J ~W Appel, E ~S Battistelli,
B Burger,
J ~A Chervenak,
A ~J Dahlen,
S Denny, [......],
L ~P Parker,
A ~J Sederberg,
S ~T Staggs,
O ~R Stryzak,
D ~S Swetz,
E ~R Switzer,
R ~J Thornton,
C Tucker,
E ~J Wollack,
Y Zhao
Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series; 08/2008
-
D ~S Swetz,
P ~A ~R Ade,
C Allen,
M Amiri,
J ~W Appel, E ~S Battistelli,
B Burger,
J ~A Chervenak,
A ~J Dahlen,
S Das, [......],
N Sehgal,
J ~L Sievers,
D ~N Spergel,
S ~T Staggs,
O ~R Stryzak,
E ~R Switzer,
R ~J Thornton,
C Tucker,
E ~J Wollack,
Y Zhao
Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series; 08/2008
