ABSTRACT We present Atacama Large Millimeter/submillimeter Array (ALMA) observations from the 2014 Long Baseline Campaign in dust continuum and spectral line emission from the HL Tau region. The ...continuum images at wavelengths of 2.9, 1.3, and 0.87 mm have unprecedented angular resolutions of 0 075 (10 AU) to 0 025 (3.5 AU), revealing an astonishing level of detail in the circumstellar disk surrounding the young solar analog HL Tau, with a pattern of bright and dark rings observed at all wavelengths. By fitting ellipses to the most distinct rings, we measure precise values for the disk inclination ( ) and position angle We obtain a high-fidelity image of the 1.0 mm spectral index ( ), which ranges from in the optically thick central peak and two brightest rings, increasing to 2.3-3.0 in the dark rings. The dark rings are not devoid of emission, and we estimate a grain emissivity index of 0.8 for the innermost dark ring and lower for subsequent dark rings, consistent with some degree of grain growth and evolution. Additional clues that the rings arise from planet formation include an increase in their central offsets with radius and the presence of numerous orbital resonances. At a resolution of 35 AU, we resolve the molecular component of the disk in HCO+ (1-0) which exhibits a pattern over LSR velocities from 2-12 km s−1 consistent with Keplerian motion around a ∼1.3 star, although complicated by absorption at low blueshifted velocities. We also serendipitously detect and resolve the nearby protostars XZ Tau (A/B) and LkH 358 at 2.9 mm.
ABSTRACT We present measurements of polarization lensing using the 150 GHz maps, which include all data taken by the BICEP2 and Keck Array Cosmic Microwave Background polarization experiments up to ...and including the 2014 observing season (BK14). Despite their modest angular resolution ( ), the excellent sensitivity (∼3 K-arcmin) of these maps makes it possible to directly reconstruct the lensing potential using only information at larger angular scales ( ). From the auto-spectrum of the reconstructed potential, we measure an amplitude of the spectrum to be (Planck ΛCDM prediction corresponds to ) and reject the no-lensing hypothesis at , which is the highest significance achieved to date using an EB lensing estimator. Taking the cross-spectrum of the reconstructed potential with the Planck 2015 lensing map yields . These direct measurements of are consistent with the ΛCDM cosmology and with that derived from the previously reported BK14 B-mode auto-spectrum ( ). We perform a series of null tests and consistency checks to show that these results are robust against systematics and are insensitive to analysis choices. These results unambiguously demonstrate that the B modes previously reported by BICEP/Keck at intermediate angular scales ( ) are dominated by gravitational lensing. The good agreement between the lensing amplitudes obtained from the lensing reconstruction and B-mode spectrum starts to place constraints on any alternative cosmological sources of B modes at these angular scales.
BICEP2. II. EXPERIMENT AND THREE-YEAR DATA SET Ade, P A R; Aikin, R W; Amiri, M ...
Astrophysical journal/The Astrophysical journal,
09/2014, Letnik:
792, Številka:
1
Journal Article
Recenzirano
Odprti dostop
We report on the design and performance of the BICEP2 instrument and on its three-year data set. BICEP2 was designed to measure the polarization of the cosmic microwave background (CMB) on angular ...scales of 1degrees-5degrees(scriptl = 40-200), near the expected peak of the B-mode polarization signature of primordial gravitational waves from cosmic inflation. Measuring B-modes requires dramatic improvements in sensitivity combined with exquisite control of systematics. The BICEP2 telescope observed from the South Pole with a 26 cm aperture and cold, on-axis, refractive optics. BICEP2 also adopted a new detector design in which beam-defining slot antenna arrays couple to transition-edge sensor (TES) bolometers, all fabricated on a common substrate. The antenna-coupled TES detectors supported scalable fabrication and multiplexed readout that allowed BICEP2 to achieve a high detector count of 500 bolometers at 150 GHz, giving unprecedented sensitivity to B-modes at degree angular scales. After optimization of detector and readout parameters, BICEP2 achieved an instrument noise-equivalent temperature of 15.8 mu Kradicals. The full data set reached Stokes Q and U map depths of 87.2 nK in square-degree pixels (5'.2 mu K) over an effective area of 384 deg super(2) within a 1000 deg super(2) field. These are the deepest CMB polarization maps at degree angular scales to date. The power spectrum analysis presented in a companion paper has resulted in a significant detection of B-mode polarization at degree scales.
ABSTRACT We have developed antenna-coupled transition-edge sensor bolometers for a wide range of cosmic microwave background (CMB) polarimetry experiments, including Bicep2, Keck Array, and the ...balloon borne Spider. These detectors have reached maturity and this paper reports on their design principles, overall performance, and key challenges associated with design and production. Our detector arrays repeatedly produce spectral bands with 20%-30% bandwidth at 95, 150, or 230 GHz. The integrated antenna arrays synthesize symmetric co-aligned beams with controlled side-lobe levels. Cross-polarized response on boresight is typically , consistent with cross-talk in our multiplexed readout system. End-to-end optical efficiencies in our cameras are routinely 35% or higher, with per detector sensitivities of NET ∼ 300 . Thanks to the scalability of this design, we have deployed 2560 detectors as 1280 matched pairs in Keck Array with a combined instantaneous sensitivity of , as measured directly from CMB maps in the 2013 season. Similar arrays have recently flown in the Spider instrument, and development of this technology is ongoing.
Abstract
We characterize Galactic dust filaments by correlating BICEP/Keck and Planck data with polarization templates based on neutral hydrogen (H
i
) observations. Dust polarization is important ...for both our understanding of astrophysical processes in the interstellar medium (ISM) and the search for primordial gravitational waves in the cosmic microwave background (CMB). In the diffuse ISM, H
i
is strongly correlated with the dust and partly organized into filaments that are aligned with the local magnetic field. We analyze the deep BICEP/Keck data at 95, 150, and 220 GHz, over the low-column-density region of sky where BICEP/Keck has set the best limits on primordial gravitational waves. We separate the H
i
emission into distinct velocity components and detect dust polarization correlated with the local Galactic H
i
but not with the H
i
associated with Magellanic Stream
i
. We present a robust, multifrequency detection of polarized dust emission correlated with the filamentary H
i
morphology template down to 95 GHz. For assessing its utility for foreground cleaning, we report that the H
i
morphology template correlates in
B
modes at a ∼10%–65% level over the multipole range 20 <
ℓ
< 200 with the BICEP/Keck maps, which contain contributions from dust, CMB, and noise components. We measure the spectral index of the filamentary dust component spectral energy distribution to be
β
= 1.54 ± 0.13. We find no evidence for decorrelation in this region between the filaments and the rest of the dust field or from the inclusion of dust associated with the intermediate velocity H
i
. Finally, we explore the morphological parameter space in the H
i
-based filamentary model.
Abstract
We report on the design and performance of the B
icep3
instrument and its first three-year data set collected from 2016 to 2018. B
icep3
is a 52 cm aperture refracting telescope designed to ...observe the polarization of the cosmic microwave background (CMB) on degree angular scales at 95 GHz. It started science observation at the South Pole in 2016 with 2400 antenna-coupled transition-edge sensor bolometers. The receiver first demonstrated new technologies such as large-diameter alumina optics, Zotefoam infrared filters, and flux-activated SQUIDs, allowing ∼10× higher optical throughput compared to the
Keck
design. B
icep3
achieved instrument noise equivalent temperatures of 9.2, 6.8, and 7.1
μ
K
CMB
s
and reached Stokes
Q
and
U
map depths of 5.9, 4.4, and 4.4
μ
K arcmin in 2016, 2017, and 2018, respectively. The combined three-year data set achieved a polarization map depth of 2.8
μ
K arcmin over an effective area of 585 square degrees, which is the deepest CMB polarization map made to date at 95 GHz.
Abstract
We present estimates of line-of-sight distortion fields derived from the 95 and 150 GHz data taken by BICEP2, BICEP3, and the Keck Array up to the 2018 observing season, leading to ...cosmological constraints and a study of instrumental and astrophysical systematics. Cosmological constraints are derived from three of the distortion fields concerning gravitational lensing from large-scale structure, polarization rotation from magnetic fields or an axion-like field, and the screening effect of patchy reionization. We measure an amplitude of the lensing power spectrum
A
L
ϕ
ϕ
=
0.95
±
0.20
. We constrain polarization rotation, expressed as the coupling constant of a Chern–Simons electromagnetic term
g
a
γ
≤ 2.6 × 10
−2
/
H
I
, where
H
I
is the inflationary Hubble parameter, and an amplitude of primordial magnetic fields smoothed over 1 Mpc
B
1Mpc
≤ 6.6 nG at 95 GHz. We constrain the rms of optical depth fluctuations in a simple “crinkly surface” model of patchy reionization, finding
A
τ
< 0.19 (2
σ
) for the coherence scale of
L
c
= 100. We show that all of the distortion fields of the 95 and 150 GHz polarization maps are consistent with simulations including lensed ΛCDM, dust, and noise, with no evidence for instrumental systematics. In some cases, the
EB
and
TB
quadratic estimators presented here are more sensitive than our previous map-based null tests at identifying and rejecting spurious
B
-modes that might arise from instrumental effects. Finally, we verify that the standard deprojection filtering in the BICEP/Keck data processing is effective at removing temperature to polarization leakage.
Background Imaging of Cosmic Extragalactic Polarization (BICEP) is a bolometric polarimeter designed to measure the inflationary B-mode polarization of the cosmic microwave background (CMB) at degree ...angular scales. During three seasons of observing at the South Pole (2006 through 2008), BICEP mapped ~2% of the sky chosen to be uniquely clean of polarized foreground emission. Here, we present initial results derived from a subset of the data acquired during the first two years. We present maps of temperature, Stokes Q and U, E and B modes, and associated angular power spectra. We demonstrate that the polarization data are self-consistent by performing a series of jackknife tests. We study potential systematic errors in detail and show that they are sub-dominant to the statistical errors. We measure the E-mode angular power spectrum with high precision at 21 <= ell <= 335, detecting for the first time the peak expected at ell ~ 140. The measured E-mode spectrum is consistent with expectations from a ΛCDM model, and the B-mode spectrum is consistent with zero. The tensor-to-scalar ratio derived from the B-mode spectrum is r = 0.02+0.31 -0.26, or r < 0.72 at 95% confidence, the first meaningful constraint on the inflationary gravitational wave background to come directly from CMB B-mode polarization.
We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of the CII 157.7 mu m fine structure line and thermal dust continuum emission from a pair of gas-rich galaxies at z = 4.7, ...BR1202-0725. This system consists of a luminous quasar host galaxy and a bright submillimeter galaxy (SMG), while a fainter star-forming galaxy is also spatially coincident within a 4" (25 kpc) region. All three galaxies are detected in the submillimeter continuum, indicating FIR luminosities in excess of 10 super(13) L sub(middot in circle) for the two most luminous objects. The SMG and the quasar host galaxy are both detected in CII line emission with luminosities L sub(CII) = (10.0 + or - 1.5) x 10 super(9) L sub(middot in circle) and L sub(CII) = (6.5 + or - 1.0) x 10 super(9) L sub(middot in circle), respectively. We estimate a luminosity ratio L sub(CII)/L sub(FIR) = (8.3 + or - 1.2) x 10 super(-4) for the starburst SMG to the north and L sub(CII)/L sub(FIR) = (2.5 + or - 0.4) x 10 super(-4) for the quasar host galaxy, in agreement with previous high-redshift studies that suggest lower CII-to-FIR luminosity ratios in quasars than in starburst galaxies. The third fainter object with a flux density S sub(340 GHz) = 1.9 + or - 0.3 mJy is coincident with a Ly alpha emitter and is detected in HST ACS F775W and F814W images but has no clear counterpart in the H band. Even if this third companion does not lie at a redshift similar to BR1202-0725, the quasar and the SMG represent an overdensity of massive, infrared luminous star-forming galaxies within 1.3 Gyr of the big bang.
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