Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userFinding Early Supernovae at 5 $< z <$ 12 with Frontier Fields
82
0
0.0
(
0
)
Authors
Daniel J. Whalen
Ask ChatGPT about the research
No Arabic abstract
Supernovae are important probes of the properties of stars at high redshifts because they can be detected at early epochs and their masses can be inferred from their light curves. Direct detection of the first cosmic explosions in the universe will only be possible with JWST, WFIRST and the next generation of extremely large telescopes. But strong gravitational lensing by massive clusters, like those in the Frontier Fields, could reveal supernovae at slightly lower redshifts now by magnifying their flux by factors of 10 or more. We find that Frontier Fields will likely discover dozens of core-collapse supernovae at 5 $ < z <$ 12. Future surveys of cluster lenses similar in scope to Frontier Fields by JWST might find hundreds of these events out to $z sim$ 15 - 17. Besides revealing the masses of early stars, these ancient supernovae could also constrain cosmic star formation rates in the era of first galaxy formation.
rate research
Read More
Multiwavelength deep observations are a key tool to understand the origin of the diffuse light in clusters of galaxies: the intra-cluster light (ICL). For this reason, we take advantage of the Hubble Frontier Fields survey to investigate the properties of the stellar populations of the ICL of its 6 massive intermediate redshift (0.3<z<0.6) clusters. We carry on this analysis down to a radial distance of ~120 kpc from the brightest cluster galaxy. We found that the average metallicity of the ICL is [Fe/H] ~-0.5, compatible with the value of the outskirts of the Milky Way. The mean stellar ages of the ICL are between 2 to 6 Gyr younger than the most massive galaxies of the clusters. Those results suggest that the ICL of these massive (> 10^15 Msol) clusters is formed by the stripping of MW-like objects that have been accreted at z<1, in agreement with current simulations. We do not find any significant increase in the fraction of light of the ICL with cosmic time, although the redshift range explored is narrow to derive any strong conclusion. When exploring the slope of the stellar mass density profile, we found that the ICL of the HFF clusters follows the shape of their underlying dark matter haloes, in agreement with the idea that the ICL is the result of the stripping of galaxies at recent times.
Supernovae (SNe) could be powerful probes of the properties of stars and galaxies at high redshifts in future surveys. Wide fields and longer exposure times are required to offset diminishing star formation rates and lower fluxes to detect useful numbers of events at high redshift. In principle, the Large Synoptic Survey Telescope (LSST) could discover large numbers of early SNe because of its wide fields but only at lower redshifts because of its AB mag limit of ~ 24. But gravitational lensing by galaxy clusters and massive galaxies could boost flux from ancient SNe and allow LSST to detect them at earlier times. Here, we calculate detection rates for lensed SNe at z ~ 5 - 7 for LSST. We find that the LSST Wide Deep Fast survey could detect up to 120 lensed Population (Pop) I and II SNe but no lensed Pop III SNe. Deep-drilling programs in a single 10 square degree FoV could detect Pop I and II core-collapse SNe and Pop III pair-instability SNe at AB magnitudes of 27 - 28 and 26, respectively. An alternative deep survey over 80 nights with a one-year cadence could find ~ 8 Pop III SNe.
We present the largest homogeneous survey of $z>4.4$ damped Lyman-$alpha$ systems (DLAs) using the spectra of 163 QSOs that comprise the Giant Gemini GMOS (GGG) survey. With this survey we make the most precise high-redshift measurement of the cosmological mass density of neutral hydrogen, $Omega_{rm HI}$. At such high redshift important systematic uncertainties in the identification of DLAs are produced by strong intergalactic medium absorption and QSO continuum placement. These can cause spurious DLA detections, result in real DLAs being missed, or bias the inferred DLA column density distribution. We correct for these effects using a combination of mock and higher-resolution spectra, and show that for the GGG DLA sample the uncertainties introduced are smaller than the statistical errors on $Omega_{rm HI}$. We find $Omega_{rm HI}=0.98^{+0.20}_{-0.18}times10^{-3}$ at $langle zrangle=4.9$, assuming a 20% contribution from lower column density systems below the DLA threshold. By comparing to literature measurements at lower redshifts, we show that $Omega_{rm HI}$ can be described by the functional form $Omega_{rm HI}(z)propto(1+z)^{0.4}$. This gradual decrease from $z=5$ to $0$ is consistent with the bulk of HI gas being a transitory phase fuelling star formation, which is continually replenished by more highly-ionized gas from the intergalactic medium, and from recycled galactic winds.
We present results of optical spectroscopic observations of candidates of Lyman Break Galaxies (LBGs) at $z sim 5$ in the region including the GOODS-N and the J0053+1234 region by using GMOS-N and GMOS-S, respectively. Among 25 candidates, five objects are identified to be at $z sim 5$ (two of them were already identified by an earlier study) and one object very close to the color-selection window turned out to be a foreground galaxy. With this spectroscopically identified sample and those from previous studies, we derived the lower limits on the number density of bright ($M_{UV}<-22.0$ mag) LBGs at $z sim 5$. These lower limits are comparable to or slightly smaller than the number densities of UV luminosity functions (UVLFs) that show the smaller number density among $z sim 5$ UVLFs in literature. However, by considering that there remain many LBG candidates without spectroscopic observations, the number density of bright LBGs is expected to increase by a factor of two or more. The evidence for the deficiency of UV luminous LBGs with large Ly$alpha$ equivalent widths was reinforced. We discuss possible causes for the deficiency and prefer the interpretation of dust absorption.
We study the dynamics of Abell 370 (A370), a highly massive Hubble Frontier Fields galaxy cluster, using self-consistent three-dimensional N-body/hydrodynamical simulations. Our simulations are constrained by X-ray, optical spectroscopic and gravitational lensing, and Sunyaev-Zeldovich (SZ) effect observations. Analyzing archival Chandra observations of A370 and comparing the X-ray morphology to the latest gravitational lensing mass reconstruction, we find offsets of ~30 kpc and ~100 kpc between the two X-ray surface brightness peaks and their nearest mass surface density peaks, suggesting that it is a merging system, in agreement with previous studies. Based on our dedicated binary cluster merger simulations, we find that initial conditions of the two progenitors with virial masses of 1.7 x 10^(15) M_sun and 1.6 x 10^(15) M_sun, an infall velocity of 3500 km/s, and an impact parameter of 100 kpc can explain the positions and the offsets between the peaks of the X-ray emission and mass surface density, the amplitude of the integrated SZ signal, and the observed relative line-of-sight velocity. Moreover, our best model reproduces the observed velocity dispersion of cluster member galaxies, which supports the large total mass of A370 derived from weak lensing. Our simulations suggest that A370 is a major merger after the second core passage in the infalling phase, just before the third core passage. In this phase, the gas has not settled down in the gravitational potential well of the cluster, which explains why A370 does not follow closely the galaxy cluster scaling relations.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
