(ProQuest: ... denotes formulae and/or non-USASCII text omitted)We present a comprehensive analysis of strong-lensing, weak-lensing shear and magnification data for a sample of 16 X-ray-regular and 4 ...high-magnification galaxy clusters at 0.19 ... 0.69 selected from Cluster Lensing And Supernova survey with Hubble (CLASH). Our analysis combines constraints from 16-band Hubble Space Telescope observations and wide-field multi-color imaging taken primarily with Suprime-Cam on the Subaru Telescope, spanning a wide range of cluster radii (10''-16'). We reconstruct surface mass density profiles of individual clusters from a joint analysis of the full lensing constraints, and determine masses and concentrations for all of the clusters. We find the internal consistency of the ensemble mass calibration to be < or =5% + or - 6% in the one-halo regime (200-2000 kpc h super(-1)) compared to the CLASH weak-lensing-only measurements of Umetsu et al. For the X-ray-selected subsample of 16 clusters, we examine the concentration-mass (c-M) relation and its intrinsic scatter using a Bayesian regression approach. Our model yields a mean concentration of ... and an intrinsic scatter of ... ,which is in excellent agreement with Lambda cold dark matter predictions when the CLASH selection function based on X-ray morphological regularity and the projection effects are taken into account. We also derive an ensemble-averaged surface mass density profile for the X-ray-selected subsample by stacking their individual profiles. The stacked lensing signal is detected at 33sigma significance over the entire radial range < or =4000 kpc h super(-1), accounting for the effects of intrinsic profile variations and uncorrelated large-scale structure along the line of sight. The stacked mass profile is well described by a family of density profiles predicted for cuspy dark-matter-dominated halos in gravitational equilibrium, namely, the Navarro-Frenk-White (NFW), Einasto, and DARKexp models, whereas the single power-law, cored isothermal and Burkert density profiles are disfavored by the data. We show that cuspy halo models that include the large-scale two-halo term provide improved agreement with the data. For the NFW halo model, we measure a mean concentration of ... , demonstrating consistency between the complementary analysis methods.
ABSTRACT
A new window to observing individual stars and other small sources at cosmological distances was opened recently, with the detection of several caustic-crossing events in galaxy cluster ...fields. Many more such events are expected soon from dedicated campaigns with the Hubble Space Telescope and the James Webb Space Telescope. These events can not only teach us about the lensed sources themselves, such as individual high-redshift stars, star clusters, or accretion discs, but through their light curves they also hold information about the point-mass function of the lens, and thus, potentially, the composition of dark matter. We present here a simple method for simulating light curves of such events, i.e. the change in apparent magnitude of the source as it sweeps over the net of caustics generated by microlenses embedded around the critical region of the lens. The method is recursive and so any reasonably sized small source can be accommodated, down to sub-solar scales, in principle. We compare the method, which we dub Adaptive Boundary Method, with other common methods such as simple inverse ray shooting, and demonstrate that it is significantly more efficient and accurate in the small-source and high-magnification regime of interest. A python version of the code is made publicly available in an open-source fashion for simulating future events.
The ubiquity of Lyman alpha (Ly ) emission in a sample of four bright O iii-strong star-forming galaxies with redshifts above seven has led to the suggestion that such luminous sources represent a ...distinct population compared with their fainter, more numerous counterparts. The presence of Ly emission within the reionization era could indicate that these sources created early ionized bubbles due to their unusually strong radiation, possibly because of the presence of active galactic nuclei. To test this hypothesis, we secured long integration spectra with XSHOOTER on the VLT for three sources selected to have similar luminosities and prominent excess fluxes in the IRAC 3.6 or 4.5 m band, usually attributed to strong O iii emission. We secured additional spectroscopy for one of these galaxies at z = 7.15 using MOSFIRE at the Keck telescope. For the most well-studied source in our sample with the strongest IRAC excess, we detect significant nebular emission from He ii and N v indicative of a non-thermal source. For the other two sources at z = 6.81 and z = 6.85, for which no previous optical/near-infrared spectroscopy was available, Ly is seen in one and C iii emission in the other. Although based on a modest sample, our results further support the hypothesis that the phenomenon of intense O iii emission is associated preferentially with sources lying in early ionized bubbles. However, even though one of our sources at z = 7.15 suggests the presence of non-thermal radiation, such ionized bubbles may not uniquely arise in this manner. We discuss the unique advantages of extending such challenging diagnostic studies with JWST.
Abstract
On 2022 July 8, NASA shared (
https://www.nasa.gov/feature/goddard/2022/nasa-shares-list-of-cosmic-targets-for-webb-telescope-s-first-images
) the list of five public showcase targets that ...have been observed with the new James Webb Space Telescope (JWST) and whose data—at the time of writing—are expected to be released to the public around Tuesday, July 12. One of these targets is the galaxy cluster SMACS J0723.3−7327 (
z
= 0.39), which acts as a gravitational lens and was recently imaged with the Hubble Space Telescope (HST) in the framework of the Reionization Lensing Cluster Survey (RELICS). To facilitate studies by the community with the upcoming JWST data, we publish here a strong-lensing model for SMACS J0723.3−7327—including mass density and magnification maps. We identify five multiple-image families in the HST imaging. For three of them, system membership and redshift are secured by public spectroscopic data. For the remaining two systems, we rely on robust photometric redshift estimates. We use the
Light-Traces-Mass
lens modeling method, which complements the parametric models already available in the RELICS repository and elsewhere and thus helps span a representative range of solutions. The new model published here can be accessed on the RELICS website at MAST. It will be interesting to examine which properties of the mass models change and improve, and by how much, when the JWST data are incorporated.
ABSTRACT We discuss spatially resolved emission line spectroscopy secured for a total sample of 15 gravitationally lensed star-forming galaxies at a mean redshift of based on Keck laser-assisted ...adaptive optics observations undertaken with the recently improved OSIRIS integral field unit (IFU) spectrograph. By exploiting gravitationally lensed sources drawn primarily from the CASSOWARY survey, we sample these sub-L galaxies with source-plane resolutions of a few hundred parsecs ensuring well-sampled 2D velocity data and resolved variations in the gas-phase metallicity. Such high spatial resolution data offer a critical check on the structural properties of larger samples derived with coarser sampling using multiple-IFU instruments. We demonstrate how kinematic complexities essential to understanding the maturity of an early star-forming galaxy can often only be revealed with better sampled data. Although we include four sources from our earlier work, the present study provides a more representative sample unbiased with respect to emission line strength. Contrary to earlier suggestions, our data indicate a more diverse range of kinematic and metal gradient behavior inconsistent with a simple picture of well-ordered rotation developing concurrently with established steep metal gradients in all but merging systems. Comparing our observations with the predictions of hydrodynamical simulations suggests that gas and metals have been mixed by outflows or other strong feedback processes, flattening the metal gradients in early star-forming galaxies.
We outline our methods for obtaining high-precision mass profiles, combining independent weak-lensing distortion, magnification, and strong-lensing measurements. For massive clusters, the strong- and ...weak-lensing regimes contribute equal logarithmic coverage of the radial profile. The utility of high-quality data is limited by the cosmic noise from large-scale structure along the line of sight. This noise is overcome when stacking clusters, as too are the effects of cluster asphericity and substructure, permitting a stringent test of theoretical models. We derive a mean radial mass profile of four similar mass clusters of high-quality Hubble Space Telescope and Subaru images, in the range R = 40-2800 kpc h --1, where the inner radial boundary is sufficiently large to avoid smoothing from miscentering effects. The stacked mass profile is detected at 58 Delta *s significance over the entire radial range, with the contribution from the cosmic noise included. We show that the projected mass profile has a continuously steepening gradient out to beyond the virial radius, in remarkably good agreement with the standard Navarro-Frenk-White form predicted for the family of cold dark matter (CDM) dominated halos in gravitational equilibrium. The central slope is constrained to lie in the range, --dln Delta *r/dln r = 0.89+0.27 -- 0.39. The mean concentration is c vir = 7.68+0.42 -- 0.40 (at M vir = 1.54+0.11 -- 0.10 X 1015 M h --1), which is high for relaxed, high-mass clusters, but consistent with Delta *LCDM when a sizable projection bias estimated from N-body simulations is considered. This possible tension will be more definitively explored with new cluster surveys, such as CLASH, LoCuSS, Subaru Hyper Suprime-Cam, and XXM-XXL, to construct the c vir-M vir relation over a wider mass range.
We directly construct model-independent mass profiles of galaxy clusters from combined weak-lensing distortion and magnification measurements within a Bayesian statistical framework, which allows for ...a full parameter-space extraction of the underlying signal. This method applies to the full range of radius outside the Einstein radius, and recovers the absolute mass normalization. We apply our method to deep Subaru imaging of five high-mass (>1015 M ) clusters, A1689, A1703, A370, Cl0024+17, and RXJ1347--11, to obtain accurate profiles beyond the virial radius (r vir). For each cluster, the lens distortion and magnification data are shown to be consistent with each other, and the total signal-to-noise ratio of the combined measurements ranges from 13 to 24 per cluster. We form a model-independent mass profile from stacking the clusters, which is detected at 37 Delta *s out to R 1.7r vir. The projected logarithmic slope Delta *g2D(R) = dln Delta *S/dln R steepens from Delta *g2D = --1.01 ? 0.09 at R 0.1r vir to Delta *g2D = --1.92 ? 0.51 at R 0.9r vir. We also derive for each cluster inner strong-lensing-based mass profiles from deep Advanced Camera for Surveys observations with the Hubble Space Telescope, which we show overlap well with the outer Subaru-based profiles and together are well described by a generalized form of the Navarro-Frenk-White profile, except for the ongoing merger RXJ1347--11, with modest variations in the central cusp slope (--dln Delta *r/dln r 0.9). The improvement here from adding the magnification measurements is significant, ~30% in terms of cluster mass profile measurements, compared with the lensing distortion signal.
The high concentrations derived for several strong-lensing clusters present a major inconsistency between theoretical Λ cold dark matter (ΛCDM) expectations and measurements. Triaxiality and ...orientation biases might be at the origin of this disagreement, as clusters elongated along the line of sight would have a relatively higher projected mass density, boosting the resulting lensing properties. Analyses of statistical samples can probe further these effects and crucially reduce biases. In this work we perform a fully triaxial strong-lensing analysis of the 12 Massive Cluster Survey (MACS) clusters at z > 0.5, a complete X-ray-selected sample, and fully account for the impact of the intrinsic 3D shapes on their strong-lensing properties. We first construct strong-lensing mass models for each cluster based on multiple images, and fit projected ellipsoidal Navarro-Frenk-White haloes with arbitrary orientations to each mass distribution. We then invert the measured surface mass densities using Bayesian statistics. Although the Einstein radii of this sample are significantly larger than those predicted by ΛCDM, here we find that the mass-concentration relation is in full agreement with results from N-body simulations. The z > 0.5 MACS clusters suffer from a moderate form of the orientation bias as may be expected for X-ray-selected samples. Being mostly unrelaxed, at a relatively high redshift, with high X-ray luminosity and notable substructures, these clusters may lie outside the standard concentration-Einstein radius relation. Our results remark the importance of triaxiality and properly selected samples for understanding galaxy clusters properties and suggest that for higher-z, unrelaxed low-concentration clusters form a different class of prominent strong gravitational lenses. Arc redshift confirmation and weak-lensing data in the outer region are needed to further refine our analysis.
In 1964, Refsdal hypothesized that a supernova whose light traversed multiple paths around a strong gravitational lens could be used to measure the rate of cosmic expansion. We report the discovery ...of such a system. In Hubble Space Telescope imaging, we have found four images of a single supernova forming an Einstein cross configuration around a redshift z = 0.54 elliptical galaxy in the MACS J1149.6+2223 cluster. The cluster's gravitational potential also creates multiple images of the z = 1.49 spiral supernova host galaxy, and a future appearance of the supernova elsewhere in the cluster field is expected. The magnifications and staggered arrivals of the supernova images probe the cosmic expansion rate, as well as the distribution of matter in the galaxy and cluster lenses.
Full text
Available for:
BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Abstract
The James Webb Space Telescope is now detecting early black holes (BHs) as they transition from “seeds” to supermassive BHs. Recently, Bogdan et al. reported the detection of an X-ray ...luminous supermassive BH, UHZ-1, with a photometric redshift at
z
> 10. Such an extreme source at this very high redshift provides new insights on seeding and growth models for BHs given the short time available for formation and growth. Harnessing the exquisite sensitivity of JWST/NIRSpec, here we report the spectroscopic confirmation of UHZ-1 at
z
= 10.073 ± 0.002. We find that the NIRSpec/Prism spectrum is typical of recently discovered
z
≈ 10 galaxies, characterized primarily by star formation features. We see no clear evidence of the powerful X-ray source in the rest-frame UV/optical spectrum, which may suggest heavy obscuration of the central BH, in line with the Compton-thick column density measured in the X-rays. We perform a stellar population fit simultaneously to the new NIRSpec spectroscopy and previously available photometry. The fit yields a stellar-mass estimate for the host galaxy that is significantly better constrained than prior photometric estimates (
M
⋆
∼
1.4
−
0.4
+
0.3
×
10
8
M
⊙
). Given the predicted BH mass (
M
BH
∼ 10
7
–10
8
M
⊙
), the resulting ratio of
M
BH
/
M
⋆
remains 2 to 3 orders of magnitude higher than local values, thus lending support to the heavy seeding channel for the formation of supermassive BHs within the first billion years of cosmic evolution.
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