Galaxy intrinsic alignment (IA) is a source of both systematic contamination of cosmic shear measurement and its cosmological applications and valuable information on the large-scale structure of the ...universe and galaxy formation. The self-calibration (SC) method was designed to separate IA from cosmic shear, free of IA modeling. It was first successfully applied to the KiDS450 and KV450 data. We improve the SC method in several aspects and apply it to the DECaLS DR3 shear + photo-z catalog and significantly improve the IA detection to ∼14 . We find a strong dependence of IA on galaxy color, with strong IA signal (∼17.6 ) for red galaxies, while the IA signal for blue galaxies is consistent with zero. The detected IAs for red galaxies are in reasonable agreement with the nonlinear tidal alignment model, and the inferred IA amplitude increases with redshift. Our measurements rule out the constant IA amplitude assumption at ∼3.9 for the red sample. We address the systematics in the SC method carefully and perform several sanity checks. We discuss various caveats, such as redshift/shear calibrations and possible improvements in the measurement, theory, and parameter fitting that will be addressed in future works.
Observations of the cosmic microwave background indicate that baryons account for 5 per cent of the Universe's total energy content. In the local Universe, the census of all observed baryons falls ...short of this estimate by a factor of two. Cosmological simulations indicate that the missing baryons have not condensed into virialized haloes, but reside throughout the filaments of the cosmic web (where matter density is larger than average) as a low-density plasma at temperatures of 10(5)-10(7) kelvin, known as the warm-hot intergalactic medium. There have been previous claims of the detection of warm-hot baryons along the line of sight to distant blazars and of hot gas between interacting clusters. These observations were, however, unable to trace the large-scale filamentary structure, or to estimate the total amount of warm-hot baryons in a representative volume of the Universe. Here we report X-ray observations of filamentary structures of gas at 10(7) kelvin associated with the galaxy cluster Abell 2744. Previous observations of this cluster were unable to resolve and remove coincidental X-ray point sources. After subtracting these, we find hot gas structures that are coherent over scales of 8 megaparsecs. The filaments coincide with over-densities of galaxies and dark matter, with 5-10 per cent of their mass in baryonic gas. This gas has been heated up by the cluster's gravitational pull and is now feeding its core. Our findings strengthen evidence for a picture of the Universe in which a large fraction of the missing baryons reside in the filaments of the cosmic web.
The far-infrared fine-structure line C ii at 1900.5 GHz is known to be one of the brightest cooling lines in local galaxies, and therefore it has been suggested to be an efficient tracer for star ...formation in very high redshift galaxies. However, recent results for galaxies at z > 6 have yielded numerous non-detections in star-forming galaxies, except for quasars and submillimetre galaxies. We report the results of ALMA observations of two lensed, star-forming galaxies at z = 6.029 and z = 6.703. The galaxy A383-5.1 (star formation rate SFR of 3.2 M⊙ yr−1 and magnification of μ = 11.4 ± 1.9) shows a line detection with $L_{\rm C\,\small {II}} = 8.9\times 10^{6}$ L⊙, making it the lowest $L_{\rm C\,\small {II}}$ detection at z > 6. For MS0451-H (SFR = 0.4 M⊙ yr−1 and μ = 100 ± 20) we provide an upper limit of $L_{\rm C\,\small {II}} < 3\times 10^{5}$ L⊙, which is 1 dex below the local SFR–$L_{\rm C\,\small {II}}$ relations. The results are consistent with predictions for low-metallicity galaxies at z > 6; however, other effects could also play a role in terms of decreasing LCII. The detection of A383-5.1 is encouraging and suggests that detections are possible, but much fainter than initially predicted.
Extending over three Hubble Space Telescope (HST) cycles, the Hubble Frontier Fields (HFF) initiative constitutes the largest commitment ever of HST time to the exploration of the distant Universe ...via gravitational lensing by massive galaxy clusters. Here, we present models of the mass distribution in the six HFF cluster lenses, derived from a joint strong- and weak-lensing analysis anchored by a total of 88 multiple-image systems identified in existing HST data. The resulting maps of the projected mass distribution and of the gravitational magnification effectively calibrate the HFF clusters as gravitational telescopes. Allowing the computation of search areas in the source plane, these maps are provided to the community to facilitate the exploitation of forthcoming HFF data for quantitative studies of the gravitationally lensed population of background galaxies. Our models of the gravitational magnification afforded by the HFF clusters allow us to quantify the lensing-induced boost in sensitivity over blank-field observations and predict that galaxies at z > 10 and as faint as m(AB) = 32 will be detectable, up to 2 mag fainter than the limit of the Hubble Ultra Deep Field.
We study the evolution of star-forming galaxies with over the redshift range of 0.7 < z < 1.2 using the emission-line galaxies (ELGs) in the extended Baryon Oscillation Spectroscopic Survey (eBOSS). ...By applying the incomplete conditional stellar mass function (SMF) model proposed in Guo et al., we simultaneously constrain the sample completeness, the stellar-halo mass relation (SHMR), and the quenched galaxy fraction. We obtain the intrinsic SMFs for star-forming galaxies in the redshift bins of 0.7 < z < 0.8, 0.8 < z < 0.9, 0.9 < z < 1.0, and 1.0 < z < 1.2, as well as the SMF for all galaxies in the redshift bin of 0.7 < z < 0.8. We find that the eBOSS ELG sample only selects about 1%-10% of the star-forming galaxy population at the different redshifts, with the lower redshift samples more complete. There is only weak evolution in the SHMR of the ELGs from z = 1.2 to z = 0.7, as well as the intrinsic galaxy SMFs. Our best-fitting models show that the central ELGs at these redshifts live in halos of mass M ∼ 1012 M , while the satellite ELGs occupy slightly more massive halos of M ∼ 1012.6 M . The average satellite fraction of the observed ELGs varies from 13% to 17%, with the galaxy bias increasing from 1.1 to 1.4 from z = 0.7 to 1.2.
Context.
Spectroscopic surveys of massive galaxy clusters reveal the properties of faint background galaxies thanks to the magnification provided by strong gravitational lensing.
Aims.
We present a ...systematic analysis of integral-field-spectroscopy observations of 12 massive clusters, conducted with the Multi Unit Spectroscopic Explorer (MUSE). All data were taken under very good seeing conditions (∼0″.6) in effective exposure times between two and 15 h per pointing, for a total of 125 h. Our observations cover a total solid angle of ∼23 arcmin
2
in the direction of clusters, many of which were previously studied by the MAssive Clusters Survey, Frontier Fields (FFs), Grism Lens-Amplified Survey from Space and Cluster Lensing And Supernova survey with
Hubble
programmes. The achieved emission line detection limit at 5
σ
for a point source varies between (0.77–1.5) × 10
−18
erg s
−1
cm
−2
at 7000 Å.
Methods.
We present our developed strategy to reduce these observational data, detect continuum sources and line emitters in the datacubes, and determine their redshifts. We constructed robust mass models for each cluster to further confirm our redshift measurements using strong-lensing constraints, and identified a total of 312 strongly lensed sources producing 939 multiple images.
Results.
The final redshift catalogues contain more than 3300 robust redshifts, of which 40% are for cluster members and ∼30% are for lensed Lyman-
α
emitters. Fourteen percent of all sources are line emitters that are not seen in the available HST images, even at the depth of the FFs (∼29 AB). We find that the magnification distribution of the lensed sources in the high-magnification regime (
μ
= 2–25) follows the theoretical expectation of
N
(
z
) ∝
μ
−2
. The quality of this dataset, number of lensed sources, and number of strong-lensing constraints enables detailed studies of the physical properties of both the lensing cluster and the background galaxies. The full data products from this work, including the datacubes, catalogues, extracted spectra, ancillary images, and mass models, are made available to the community.
ABSTRACT
We present the joint analysis of Neutral Hydrogen (H i) Intensity Mapping observations with three galaxy samples: the Luminous Red Galaxy (LRG) and Emission Line Galaxy (ELG) samples from ...the eBOSS survey, and the WiggleZ Dark Energy Survey sample. The H i intensity maps are Green Bank Telescope observations of the redshifted $21\rm cm$ emission on $100 \, {\rm deg}^2$ covering the redshift range 0.6 < z < 1.0. We process the data by separating and removing the foregrounds present in the radio frequencies with FastI ICA. We verify the quality of the foreground separation with mock realizations, and construct a transfer function to correct for the effects of foreground removal on the H i signal. We cross-correlate the cleaned H i data with the galaxy samples and study the overall amplitude as well as the scale dependence of the power spectrum. We also qualitatively compare our findings with the predictions by a semianalytical galaxy evolution simulation. The cross-correlations constrain the quantity $\Omega _{\rm {H\,\small {I}}} b_{\rm {H\,\small {I}}} r_{\rm {H\,\small {I}},{\rm opt}}$ at an effective scale keff, where $\Omega _\rm {H\,\small {I}}$ is the H i density fraction, $b_\rm {H\,\small {I}}$ is the H i bias, and $r_{\rm {H\,\small {I}},{\rm opt}}$ the galaxy–hydrogen correlation coefficient, which is dependent on the H i content of the optical galaxy sample. At $k_{\rm eff}=0.31 \, h\,{\rm Mpc^{-1}}$ we find $\Omega _{\rm {H\,\small {I}}} b_{\rm {H\,\small {I}}} r_{\rm {H\,\small {I}},{\rm Wig}} = 0.58 \pm 0.09 \, {\rm (stat) \pm 0.05 \, {\rm (sys)}} \times 10^{-3}$ for GBT-WiggleZ, $\Omega _{\rm {H\,\small {I}}} b_{\rm {H\,\small {I}}} r_{\rm {H\,\small {I}},{\rm ELG}} = 0.40 \pm 0.09 \, {\rm (stat) \pm 0.04 \, {\rm (sys)}} \times 10^{-3}$ for GBT-ELG, and $\Omega _{\rm {H\,\small {I}}} b_{\rm {H\,\small {I}}} r_{\rm {H\,\small {I}},{\rm LRG}} = 0.35 \pm 0.08 \, {\rm (stat) \pm 0.03 \, {\rm (sys)}} \times 10^{-3}$ for GBT-LRG, at z ≃ 0.8. We also report results at $k_{\rm eff}=0.24$ and $k_{\rm eff}=0.48 \, h\,{\rm Mpc^{-1}}$. With little information on H i parameters beyond our local Universe, these are amongst the most precise constraints on neutral hydrogen density fluctuations in an underexplored redshift range.
Abstract
The concentration–mass (
c
–M) relation encodes key information about the assembly history of dark matter halos. However, its behavior at the high mass end has not been measured precisely in ...observations yet. In this paper, we report the measurement of the halo
c
–M relation with the galaxy–galaxy lensing method, using the shear catalog of the Dark Energy Camera Legacy Survey (DECaLS) Data Release 8, which covers a sky area of 9500 deg
2
. The foreground lenses are selected from the redMaPPer, LOWZ, and CMASS catalogs, with halo masses ranging from 10
13
to 10
15
M
⊙
and redshifts ranging from
z
= 0.08 to
z
= 0.65. We find that the concentration decreases with the halo mass from 10
13
to 10
14
M
⊙
, but shows a trend of upturn after the pivot point of ∼10
14
M
⊙
. We fit the measured
c
–M relation with the concentration model
c
(
M
)
=
C
0
M
10
12
M
⊙
/
h
−
γ
1
+
M
M
0
0.4
, and we get the values (
C
0
,
γ
, log
10
(
M
0
)) = (5.119
−0.185
0.183
,
0.205
−
0.010
0.010
,
14.083
−
0.133
0.130
) and (
4.875
−
0.208
0.209
,
0.221
−
0.010
0.010
,
13.750
−
0.141
0.142
) for halos with 0.08 ≤
z
< 0.35 and 0.35 ≤
z
< 0.65, respectively. We also show that the model including an upturn is favored over a simple power-law model. Our measurement provides important information for the recent argument over the massive cluster formation process.
Abstract
We perform a tomographic baryon acoustic oscillations (BAOs) analysis using the two-point galaxy correlation function measured from the combined sample of Baryon Oscillation Spectroscopic ...Survey Data Release 12 (BOSS DR12), which covers the redshift range of 0.2 < z < 0.75. Upon splitting the sample into multiple overlapping redshift slices to extract the redshift information of galaxy clustering, we obtain a measurement of DA
(z)/rd
and H(z)rd
at nine effective redshifts with the full covariance matrix calibrated using MultiDark-Patchy mock catalogues. Using the reconstructed galaxy catalogues, we obtain the precision of 1.3–2.2 per cent for DA
(z)/rd
and 2.1–6.0 per cent for H(z)rd
. To quantify the gain from the tomographic information, we compare the constraints on the cosmological parameters using our nine-bin BAO measurements, the consensus three-bin BAO and redshift space distortion measurements at three effective redshifts in Alam et al., and the non-tomographic (one-bin) BAO measurement at a single effective redshift. Comparing the nine-bin with one-bin constraint result, it can improve the dark energy Figure of Merit by a factor of 1.24 for the Chevallier–Polarski–Linder parametrization for equation-of-state parameter w
DE. The errors of w
0 and wa
from nine-bin constraints are slightly improved when compared to the three-bin constraint result.
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![[C ii] emission in z ∼ 6 st...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/1745-3925/small "[C ii] emission in z ∼ 6 strongly lensed, star-forming galaxies")
