Search

We present JWST/NIRSpec prism spectroscopy of MACS0647−JD, a triply lensed z ∼ 11 candidate discovered in Hubble Space Telescope imaging and spatially resolved by JWST imaging into two components, A and B. Spectroscopy of component A yields a spectroscopic redshift z = 10.17 based on seven detected emission lines: C iii ] λ λ 1907, 1909, [O ii ] λ 3727, [Ne iii ] λ 3869, [Ne iii ] λ 3968, H δ λ 4101, H γ λ 4340, and [O iii ] λ 4363. These are the second-most distant detections of these emission lines to date, in a galaxy observed just 460 million years after the Big Bang. Based on observed and extrapolated line flux ratios we derive a gas-phase metallicity 12 + log(O/H) ∼ 7.5–8.0, or Z ∼ (0.06–0.2) Z ⊙, ionization parameter log (U) = −1.9 ± 0.2, and an ionizing photon production efficiency log (ξ ion) = 25.2 ± 0.2 erg−1 Hz. The spectrum has a softened Ly α break, evidence for a strong Ly α damping wing. The Ly α damping wing also suppresses the F150W photometry, explaining the slightly overestimated photometric redshift z = 10.6 ± 0.3. MACS0647−JD has a stellar mass log(M / M ⊙) = 8.1 ± 0.3, including ∼6 × 107 M ⊙ in component A, most of which formed recently (within ∼20 Myr) with a star formation rate ∼ 2 ± 1 M ⊙ yr−1, all within an effective radius 70 ± 24 pc. Spectroscopy of a fainter companion galaxy C separated by a distance of ∼ 3 kpc reveals a Lyman break consistent with z ∼ 10.17. MACS0647−JD is likely the most distant galaxy merger known. [ABSTRACT FROM AUTHOR]

The Cosmic Gems arc is among the brightest and highly magnified galaxies observed at redshift z ≈ 10.2 (ref. 1). However, it is an intrinsically ultraviolet faint galaxy, in the range of those now thought to drive the reionization of the Universe2–4. Hitherto the smallest features resolved in a galaxy at a comparable redshift are between a few hundreds and a few tens of parsecs (pc)5,6. Here we report JWST observations of the Cosmic Gems. The light of the galaxy is resolved into five star clusters located in a region smaller than 70 pc. They exhibit minimal dust attenuation and low metallicity, ages younger than 50 Myr and intrinsic masses of about 106M⊙. Their lensing-corrected sizes are approximately 1 pc, resulting in stellar surface densities near 105M⊙ pc−2, three orders of magnitude higher than typical young star clusters in the local Universe7. Despite the uncertainties inherent to the lensing model, they are consistent with being gravitationally bound stellar systems, that is, proto-globular clusters. We conclude that star cluster formation and feedback likely contributed to shaping the properties of galaxies during the epoch of reionization.JWST observations of the Cosmic Gems arc resolve the light of an infant galaxy into five gravitationally bound star clusters located in a region smaller than 70 pc. [ABSTRACT FROM AUTHOR]

We study the impact of black hole nuclear activity on both the global and radial star formation rate (SFR) profiles in X-ray-selected active galactic nuclei (AGN) in the field of miniJPAS, the precursor of the much wider J-PAS project. Our sample includes 32 AGN with z < 0.3 detected via the XMM-Newton and Chandra surveys. For comparison, we assembled a control sample of 71 star-forming (SF) galaxies with similar magnitudes, sizes, and redshifts. To derive the global properties of both the AGN and the control SF sample, we used CIGALE to fit the spectral energy distributions derived from the 56 narrowband and 4 broadband filters from miniJPAS. We find that AGN tend to reside in more massive galaxies than their SF counterparts. After matching samples based on stellar mass and comparing their SFRs and specific SFRs (sSFRs), no significant differences appear. This suggests that the presence of AGN does not strongly influence overall star formation. However, when we used miniJPAS as an integral field unit (IFU) to dissect galaxies along their position angle, a different picture emerges. We find that AGN tend to be more centrally concentrated in mass with respect to SF galaxies. Moreover, we find a suppression of the sSFR up to 1Re and then an enhancement beyond 1Re, strongly contrasting with the decreasing radial profile of sSFRs in SF galaxies. This could point to an inside-out quenching of AGN host galaxies. Additionally, we examined how the radial profiles of the sSFRs in AGN and SF galaxies depend on galaxy morphology, by dividing our sample into disk-dominated (DD), pseudo-bulge (PB), and bulge-dominated (BD) systems. In DD systems, AGN exhibit a flat sSFR profile in the central regions and enhanced star formation beyond 1Re, contrasting with SF galaxies. In PB systems, SF galaxies show a decreasing sSFR profile, while AGN hosts exhibit an inside-out quenching scenario. In BD systems, both populations demonstrate consistent flat sSFR profiles. These findings suggest that the reason we do not see differences on a global scale is because star formation is suppressed in the central regions and enhanced in the outer regions of AGN host galaxies. While limited in terms of sample size, this work highlights the potential of the upcoming J-PAS as a wide-field low-resolution IFU for thousands of nearby galaxies and AGN. [ABSTRACT FROM AUTHOR]

Recent studies suggested that the ejecta velocity of Type Ia supernova (SN Ia) is a promising indicator in distinguishing the progenitor systems and explosion mechanisms. By classifying the SNe Ia based on their ejecta velocities, studies found that SNe Ia with high |$\mathrm{Si}\, {\rm{\small II}}\, \lambda 6355$| velocities (HV SNe Ia; |$v \gtrsim 12\,000$|  km s−1) tend to be physically different from their normal-velocity counterparts (NV SNe Ia). In this work, we revisit the low- z sample studied in previous work and closely look into the spatially resolved environment local to the site of SN explosion. Our results reveal a possible trend (at 2.4σ significance) that HV SNe Ia are likely associated with older stellar populations than NV SNe Ia. While the trend is inconclusive, the local host-galaxy sample studied in this work is likely skewed towards massive galaxies, limiting the parameter space that we would like to investigate from the original parent sample. Nevertheless, our results do not rule out the possibility that parameters other than the host-galaxy age (such as metallicity) could be the underlying factors driving the differences between HV and NV SNe Ia due to the limitation of our data set. [ABSTRACT FROM AUTHOR]

Standard models of structure formation allow us to predict the cosmic timescales relevant for the onset of star formation and the assembly history of galaxies at high redshifts (z > 10). The strength of the Balmer break represents a well-known diagnostic of the age and star formation history of galaxies, which enables us to compare observations with contemporary simulations – thus shedding light on the predictive power of our current models of star formation in the early Universe. Here, we measure the Balmer break strength for 23 spectroscopically confirmed galaxies at redshifts 6 ≲ z ≲ 12 using public JWST NIRSpec data from the cycle 1 GO 1433 and GO 2282 programmes (PI Coe), as well as public spectroscopic data from the JWST Deep Extragalactic Survey (JADES). We find that the range of observed Balmer break strengths agree well with that of current simulations given our measurement uncertainties. No cases of anomalously strong Balmer breaks are detected, and therefore no severe departures from the predictions of contemporary models of star formation. However, there are indications of a number of outliers in the observed distribution which have weaker Balmer breaks than predicted by simulations. [ABSTRACT FROM AUTHOR]

We present JWST/NIRSpec observations of a highly magnified star candidate at a photometric redshift of z phot ≃ 4.8, previously detected in JWST/NIRCam imaging of the strong lensing (SL) cluster MACS J0647+7015 (z  = 0.591). The spectroscopic observation allows us to precisely measure the redshift of the host arc at z spec = 4.758 ± 0.004, and the star's spectrum displays clear Lyman- and Balmer-breaks commensurate with this redshift. A fit to the spectrum suggests a B-type super-giant star of surface temperature |$T_{\mathrm{eff,B}}\simeq 15\, 000$|  K with either a redder F-type companion (⁠|$T_{\mathrm{eff,F}}\simeq 6\, 250$|  K) or significant dust attenuation (AV ≃ 0.82) along the line of sight. We also investigate the possibility that this object is a magnified young globular cluster rather than a single star. We show that the spectrum is in principle consistent with a star cluster, which could also accommodate the lack of flux variability between the two epochs. However, the lack of a counter image and the strong upper limit on the size of the object from lensing symmetry, r ≲ 0.5 pc, could indicate that this scenario is somewhat less likely – albeit not completely ruled out by the current data. The presented spectrum seen at a time when the Universe was only ∼1.2 Gyr old showcases the ability of JWST to study early stars through extreme lensing. [ABSTRACT FROM AUTHOR]

The electrical properties of graphene doped with graphite and N-pyridine and their interaction with K+ ions have been studied using the density-functional based tight-binding (DFTB) method. Pure graphene and graphene with a single vacancy are used as comparisons. A 4 × 4 × 1 unit cell was used as the base, while an enlarged supercell consisting of primitive unit cells repeated to 40 × 40 × 1 was used for sampling. The structure and the Fermi Level of the optimized graphene agreed with the experimental data. The presence of N as a dopant in a graphitic configuration shifted the Fermi level to higher levels, while N in a pyridinic configuration shifted it to lower. Both showed an increase in the intensity of electronic activity. The presence of the dopant N resulted in the widening of the bandgap in graphene. The electrical characteristics of the examined graphenes influence the strength of the interaction with K+ ions. The band structure of graphene, N-graphitic graphene, defect-graphene, and N-pyridinic graphene reveals the band opening features that influence adsorption interactions with K+ ions. The ease with which K+ ions interact on the graphene surface is facilitated by a larger bandgap energy. The bandgap energies of vacantcy-containing graphene and N-pyridine-doped graphene are larger, leading to greater K+ ion interactions. In the pyridine arrangement, the presence of N doping degrades graphene symmetry, changes Fermi levels and increases the bandgap. The greater the bandgap, the stronger the interaction of graphene with K+ ions. The interaction between K+ ions and N-pyridine-doped graphene, however, results in an energy that is too high in this approach. [ABSTRACT FROM AUTHOR]

We present Atacama Large Millimeter/submillimeter Array Band 5 observations of a galaxy at z = 1.91, GDS24569, in search of molecular gas in its vicinity via the [C i ] 3P1–3P0 line. GDS24569 is a massive (), passively evolving galaxy, characterized by compact morphology with an effective radius of ∼0.5 kpc. We apply two blind detection algorithms to the spectral data cubes and find no promising detection in or around GDS24569 out to a projected distance of ∼320 kpc, while a narrow tentative line (4.1σ) is identified at +1200 km s−1 by one of the algorithms. From the nondetection of [C i ], we place a 3σ upper limit on molecular hydrogen mass, ∼ 7.1 × 109M⊙, which converts to an extremely low gas-to-stellar mass fraction of ≲ 5%. We conduct a spectral energy distribution modeling by including optical to far-infrared data and find a considerably high (∼ 0.1%) dust-to-stellar mass ratio, i.e., ∼10–100× higher than those of local early-type galaxies. In combination with a previous result of an insufficient number of surrounding satellite galaxies, it is suggested that GDS24569 is unlikely to experience significant size evolution via satellite mergers. We discuss possible physical mechanisms that quenched GDS24569. [ABSTRACT FROM AUTHOR]

Despite decreasing cosmic star formation rate density over the last 10 Gyr, the stellar mass (M*) buildups in galaxies were still progressing during this epoch. About 50% of the current M* density in the universe was built over the last ∼8.7 Gyr. In this research, we investigated the stellar mass buildup and quenching of spatially resolved regions within massive disk galaxies over the last 10 Gyr. We apply the spectral energy distribution (SED) fitting method to SEDs of sub-galactic regions in galaxies to derive the spatially resolved distributions of SFR and M* in the galaxies. This namely pixel-to-pixel SED fitting method is applied to massive disk galaxies at 0.01 < z < 0.02 and 0.8 < z < 1.8. We found that massive disk galaxies tend to build their M* and quench their star formation progressively from the central region to the outskirts, i.e. inside-out stellar mass buildup and quenching. [ABSTRACT FROM AUTHOR]

Despite decreasing cosmic star formation rate density over the last 10 Gyr, the stellar mass (M*) buildups in galaxies were still progressing during this epoch. About 50% of the current M* density in the universe was built over the last ∼8.7 Gyr. In this research, we investigated the stellar mass buildup and quenching of spatially resolved regions within massive disk galaxies over the last 10 Gyr. We apply the spectral energy distribution (SED) fitting method to SEDs of sub-galactic regions in galaxies to derive the spatially resolved distributions of SFR and M* in the galaxies. This namely pixel-to-pixel SED fitting method is applied to massive disk galaxies at 0.01 < z < 0.02 and 0.8 < z < 1.8. We found that massive disk galaxies tend to build their M* and quench their star formation progressively from the central region to the outskirts, i.e. inside-out stellar mass buildup and quenching. [ABSTRACT FROM AUTHOR]

Despite decreasing cosmic star formation rate density over the last 10 Gyr, the stellar mass (M*) buildups in galaxies were still progressing during this epoch. About 50% of the current M* density in the universe was built over the last ∼8.7 Gyr. In this research, we investigated the stellar mass buildup and quenching of spatially resolved regions within massive disk galaxies over the last 10 Gyr. We apply the spectral energy distribution (SED) fitting method to SEDs of sub-galactic regions in galaxies to derive the spatially resolved distributions of SFR and M* in the galaxies. This namely pixel-to-pixel SED fitting method is applied to massive disk galaxies at 0.01 < z < 0.02 and 0.8 < z < 1.8. We found that massive disk galaxies tend to build their M* and quench their star formation progressively from the central region to the outskirts, i.e. inside-out stellar mass buildup and quenching. [ABSTRACT FROM AUTHOR]

We investigate a relation between surface densities of star formation rate (SFR) and stellar mass (M *) at a ∼1 kpc scale namely spatially resolved star formation main sequence (SFMS) in massive (log (M */ M ⊙) > 10.5) face-on disc galaxies at 0.01 < $$z$$ < 0.02 and 0.8 < $$z$$ < 1.8 and examine evolution of the relation. The spatially resolved SFMS of $$z$$ ∼ 0 galaxies is discussed in a companion paper. For $$z$$ ∼ 1 sample, we use eight bands imaging data set from Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey and 3D- HST and perform a pixel-to-pixel spectral energy distribution fitting to derive the spatially resolved SFR and M *. We find a linear spatially resolved SFMS in the $$z$$ ∼ 1 galaxies that lie on the global SFMS, while a ‘flattening’ at high Σ* end is found in that relation for the galaxies that lie below the global SFMS. Comparison with the spatially resolved SFMS of the $$z$$ ∼ 0 galaxies shows smaller difference in the specific SFR (sSFR) at low Σ* than that at high Σ*. This trend is consistent with the evolution of the sSFR(r) radial profile, which shows a faster decrease in the central region than in the outskirt, agrees with the inside–out quenching scenario. We then derive an empirical model for the evolution of the Σ*(r), ΣSFR(r), and sSFR(r) radial profiles. Based on the empirical model, we estimate the radial profile of the quenching time-scale and reproduce the observed spatially resolved SFMS at $$z$$ ∼ 1 and ∼0. [ABSTRACT FROM AUTHOR]

In order to construct a sample of ultra-luminous infrared galaxies (ULIRGs; with infrared luminosity L IR > 1012  L |${_{\odot} }$|⁠) at 0.5 < |$z$| < 1, we are conducting an optical follow-up program for bright 90 μm far-infrared sources with a faint optical (i < 20 mag) counterpart selected in the AKARI Far-Infrared Surveyor (FIS) Bright Source catalog (Ver.2). AKARI-FIS-V2 J0916248+073034, identified as a ULIRG at |$z$| = 0.49 in the spectroscopic follow-up observation, indicates signatures of an extremely strong outflow in its emission line profiles. Its [O  iii] 5007 Å emission line shows a full width at half-maximum (FWHM) of 1830 km s−1 and velocity shift of −770 km s−1 relative to the stellar absorption lines. Furthermore, the low-ionization [O  ii] 3726 Å 3729 Å doublet also shows a large FWHM of 910 km s−1 and velocity shift of −380 km s−1. After the removal of an unresolved nuclear component, the long-slit spectroscopy 2D image possibly shows that the outflow extends to a radius of 4 kpc. The mass outflow and energy ejection rates are estimated to be 500  M |${_{\odot} }$|  yr−1 and 4 × 1044 erg s−1, respectively, which imply that the outflow is among the most powerful ones observed in ULIRGs and quasi-stellar objects at 0.3 < |$z$| < 1.6. The co-existence of the strong outflow and intense star formation (star formation rate of 990  M |${_{\odot} }$|  yr−1) indicates that the feedback of the strong outflow has not severely affected the star-forming region of the galaxy. [ABSTRACT FROM AUTHOR]