In the past decade, submillimeter surveys have been employed to define samples of gravitationally-lensed dusty star-forming galaxies (DSFGs) at z ∼ 1 − 4. These extreme objects () appear to form ...stars prodigiously at rates of . Using all-sky Planck and WISE surveys, and wide-area Herschel surveys, we have identified the PASSAGES sample, with some of the rarest hyper-luminous IR galaxies ever discovered. We have found that their globally-averaged star formation surface densities are always sub-Eddington, typically by an order of magnitude. This may suggest that our understanding of how radiation pressure from massive stars disrupts the collapse of molecular clouds (thereby quenching star formation) is flawed—or simply that smaller physical resolutions are necessary. With the aid of lensing, we can now capture the source-plane distribution of star formation at ∼ 100pc scales, letting us identify isolated super-Eddington regions where quenching is occurring.
Abstract
The first deep field images from the James Webb Space Telescope (JWST) of the galaxy cluster SMACS J0723.3-7327 reveal a wealth of new lensed images at uncharted infrared wavelengths, with ...unprecedented depth and resolution. Here we securely identify 14 new sets of multiply imaged galaxies totaling 42 images, adding to the five sets of bright and multiply imaged galaxies already known from Hubble Space Telescope data. We find examples of arcs crossing critical curves, allowing detailed community follow-up, such as JWST spectroscopy for precise redshift determinations, and measurements of the chemical abundances and of the detailed internal gas dynamics of very distant, young galaxies. One such arc contains a pair of compact knots that are magnified by a factor of hundreds, and features a microlensed transient. We also detect an Einstein cross candidate only visible thanks to JWST’s superb resolution. Our parametric lens model is available through the following link (
https://www.dropbox.com/sh/gwup2lvks0jsqe5/AAC2RRSKce0aX-lIFCc9vhBXa?dl=0
) and will be regularly updated using additional spectroscopic redshifts. The model is constrained by 16 of these sets of multiply imaged galaxies, three of which have spectroscopic redshifts, and reproduces the multiple images to better than an rms of 0.″5, allowing for accurate magnification estimates of high-redshift galaxies. The intracluster light extends beyond the cluster members, exhibiting large-scale features that suggest a significant past dynamical disturbance. This work represents a first taste of the enhanced power JWST will have for lensing-related science.
Abstract
The PASSAGES (Planck All-Sky Survey to Analyze Gravitationally-lensed Extreme Starbursts) collaboration has recently defined a sample of 30 gravitationally lensed dusty star-forming galaxies ...(DSFGs). These rare, submillimeter-selected objects enable high-resolution views of the most extreme sites of star formation in galaxies at cosmic noon. Here, we present the first major compilation of strong lensing analyses using
lenstool
for PASSAGES, including 15 objects spanning
z
= 1.1–3.3, using complementary information from 0.″6-resolution 1.1 mm Atacama Large Millimeter/submillimeter Array and 0.″4 5 cm Jansky Very Large Array continuum imaging, in tandem with 1.6
μ
m Hubble and optical imaging with Gemini-S. Magnifications range from
μ
= 2 to 28 (median
μ
= 7), yielding intrinsic infrared luminosities of
L
IR
= 0.2–5.9 × 10
13
L
⊙
(median 1.4 × 10
13
L
⊙
) and inferred star formation rates of 170–6300
M
⊙
yr
−1
(median 1500
M
⊙
yr
−1
). These results suggest that the PASSAGES objects comprise some of the most extreme known starbursts, rivaling the luminosities of even the brightest unlensed objects, further amplified by lensing. The intrinsic sizes of far-infrared continuum regions are large (
R
e
= 1.7–4.3 kpc; median 3.0 kpc) but consistent with
L
IR
–
R
e
scaling relations for
z
> 1 DSFGs, suggesting a widespread spatial distribution of star formation. With modestly high angular resolution, we explore if these objects might be maximal starbursts. Instead of approaching Eddington-limited surface densities, above which radiation pressure will disrupt further star formation, they are safely sub-Eddington—at least on global, galaxy-integrated scales.
ABSTRACT
Hyperluminous infrared galaxies (HyLIRGs) are the most extreme star-forming systems observed in the early Universe, and their properties still elude comprehensive understanding. We have ...undertaken a large XMM–Newton observing programme to probe the total accreting black hole population in three HyLIRGs at z = 2.12, 3.25, and 3.55, gravitationally lensed by foreground galaxies. Selected from the Planck All-Sky Survey to Analyse Gravitationally lensed Extreme Starbursts (PASSAGES), these HyLIRGs have apparent infrared luminosities >1014 L⊙. Our observations revealed X-ray emission in each of them. PJ1336+49 appears to be dominated by high-mass X-ray binaries (HMXBs). Remarkably, the luminosity of this non-AGN X-ray emission exceeds by a factor of about 3 the value obtained by calibration with local galaxies with much lower star formation rates. This enhanced X-ray emission most likely highlights the efficacy of dynamical HMXB production within compact clusters, which is an important mode of star formation in HyLIRGs. The remaining two (PJ0116−24 and PJ1053+60) morphologically and spectrally exhibit a compact X-ray component in addition to the extended non-AGN X-ray emission, indicating the presence of Active Galactic Nuclei (AGNs). The AGN appears to be centrally located in the reconstructed source plane images of PJ0116−24, which manifests its star-forming activity predominantly within an extended galactic disc. In contrast, the AGN in the field of PJ1053+60 is projected 60 kpc away from the extreme star-forming galaxy and could be ejected from it. These results underline the synergistic potential of deep X-ray observations with strong lensing for the study of high-energy astrophysical phenomena in HyLIRGs.
Abstract
We report ALMA detections of C
ii
and a dust continuum in Az9, a multiply imaged galaxy behind the Frontier Field cluster MACS J0717.5+3745. The bright C
ii
emission line provides a ...spectroscopic redshift of
z
= 4.274. This strongly lensed (
μ
= 7 ± 1) galaxy has an intrinsic stellar mass of only 2 × 10
9
M
⊙
and a total star formation rate of 26
M
⊙
yr
−1
(∼80% of which is dust-obscured). Using public magnification maps, we reconstruct the C
ii
emission in the source plane to reveal a stable, rotation-dominated disk with
V
/
σ
= 5.3, which is >2× higher than predicted from simulations for similarly high-redshift, low-mass galaxies. In the source plane, the C
ii
disk has a half-light radius of 1.8 kpc and, along with the dust, is spatially offset from the peak of the stellar light by 1.4 kpc. Az9 is not deficient in C
ii
;
L
C
II
/
L
IR
= 0.0027, consistent with local and high-redshift normal star-forming galaxies. While dust-obscured star formation is expected to dominate in higher-mass galaxies, such a large reservoir of dust and gas in a lower-mass disk galaxy 1.4 Gyr after the Big Bang challenges our picture of early galaxy evolution. Furthermore, the prevalence of such low-mass dusty galaxies has important implications for the selection of the highest-redshift dropout galaxies with JWST. As one of the lowest stellar mass galaxies at
z
> 4 to be detected in a dust continuum and C
ii
, Az9 is an excellent laboratory in which to study early dust enrichment in the interstellar medium.
Abstract
The massive galaxy cluster El Gordo (
z
= 0.87) imprints multitudes of gravitationally lensed arcs onto James Webb Space Telescope Near-Infrared Camera (NIRCam) images. Eight bands of NIRCam ...imaging were obtained in the “Prime Extragalactic Areas for Reionization and Lensing Science” (“PEARLS”) program. Point-spread function–matched photometry across Hubble Space Telescope and NIRCam filters supplies new photometric redshifts. A new light-traces-mass lens model based on 56 image multiplicities identifies the two mass peaks and yields a mass estimate within 500 kpc of (7.0 ± 0.30) × 10
14
M
⊙
. A search for substructure in the 140 cluster members with spectroscopic redshifts confirms the two main mass components. The southeastern mass peak that contains the brightest cluster galaxy is more tightly bound than the northwestern one. The virial mass within 1.7 Mpc is (5.1 ± 0.60)×10
14
M
⊙
, lower than the lensing mass. A significant transverse velocity component could mean the virial mass is underestimated. We contribute one new member to the previously known
z
= 4.32 galaxy group. Intrinsic (delensed) positions of the five secure group members span a physical extent of ∼60 kpc. 13 additional candidates selected by spectroscopic/photometric constraints are small and faint, with a mean intrinsic luminosity ∼2.2 mag fainter than
L
*
. NIRCam imaging admits a fairly wide range of brightnesses and morphologies for the group members, suggesting a more diverse galaxy population in this galaxy overdensity.
Abstract
A full understanding of how unusually large ultradiffuse galaxies (UDGs) fit into our conventional theory of galaxy formation remains elusive, despite the large number of objects identified ...locally. A natural extension of UDG research is the study of similar galaxies at higher redshift to establish how their properties may evolve over time. However, this has been a challenging task given how severely systematic effects and cosmological surface brightness dimming inhibit our ability to analyze low surface brightness galaxies at high
z
. Here, we present a sample of low stellar surface density galaxies (LDGs) at moderate redshift, likely the progenitors of local UDGs, identified using deep near-IR observations of the El Gordo cluster at
z
= 0.87 with JWST. By stacking eight NIRCAM filters, we reach an apparent surface brightness sensitivity of 24.59 mag arcsec
−2
, which is faint enough to be complete to the bright end of the LDG population. Our analysis identifies significant differences between this population and UDGs observed locally, such as their color and size distributions, which suggest that the UDG progenitors at high
z
are bluer and more extended than UDGs at
z
= 0. This suggests that multiple mechanisms are responsible for the UDG formation and that prolonged transformation of cluster dwarfs is not a primary UDG formation mechanism at high
z
. Furthermore, we find a slight overabundance of LDGs in El Gordo, and, in contrast to findings in local clusters, our analysis does not show a deficit of LDGs in the center of El Gordo, implying that tidal destruction of LDGs is significant between
z
= 0.87 and
z
= 0.
Abstract
A wealth of observations have long suggested that the vast majority of isolated classical dwarf galaxies (
M
*
= 10
7
–10
9
M
⊙
) are currently star forming. However, recent observations of ...the large abundance of “ultra-diffuse galaxies” beyond the reach of previous large spectroscopic surveys suggest that our understanding of the dwarf galaxy population may be incomplete. Here we report the serendipitous discovery of an isolated quiescent dwarf galaxy in the nearby Universe, which was imaged as part of the JWST PEARLS Guaranteed Time Observation program. Remarkably, individual red-giant branch stars are visible in this near-IR imaging, suggesting a distance of 30 ± 4 Mpc, and a wealth of archival photometry point to an sSFR of 2 × 10
−11
yr
−1
and star formation rate of 4 × 10
−4
M
⊙
yr
−1
. Spectra obtained with the Lowell Discovery Telescope find a recessional velocity consistent with the Hubble Flow and >1500 km s
−1
separated from the nearest massive galaxy in Sloan Digital Sky Survey suggesting that this galaxy was either quenched from internal mechanisms or had a very high-velocity (≳1000 km s
−1
) interaction with a nearby massive galaxy in the past. This analysis highlights the possibility that many nearby quiescent dwarf galaxies are waiting to be discovered and that JWST has the potential to resolve them.
Abstract
A Type Ia supernova (SN) at
z
= 1.78 was discovered in James Webb Space Telescope Near Infrared Camera imaging of the galaxy cluster PLCK G165.7+67.0 (G165;
z
= 0.35). The SN is situated ...1.5–2 kpc from the host-galaxy nucleus and appears in three different locations as a result of gravitational lensing by G165. These data can yield a value for Hubble’s constant using time delays from this multiply imaged SN Ia that we call “SN H0pe.” Over the cluster, we identified 21 image multiplicities, confirmed five of them using the Near-Infrared Spectrograph, and constructed a new lens model that gives a total mass within 600 kpc of (2.6 ± 0.3) × 10
14
M
⊙
. The photometry uncovered a galaxy overdensity coincident with the SN host galaxy. NIRSpec confirmed six member galaxies, four of which surround the SN host galaxy with relative velocity ≲900 km s
−1
and projected physical extent ≲33 kpc. This compact galaxy group is dominated by the SN host galaxy, which has a stellar mass of (5.0 ± 0.1) × 10
11
M
⊙
. The group members have specific star formation rates of 2–260 Gyr
−1
derived from the H
α
-line fluxes corrected for stellar absorption, dust extinction, and slit losses. Another group centered on a strongly lensed dusty star-forming galaxy is at
z
= 2.24. The total (unobscured and obscured) SFR of this second galaxy group is estimated to be (≳ 100
M
⊙
yr
−1
), which translates to a supernova rate of ∼1 SNe yr
−1
, suggesting that regular monitoring of this cluster may yield additional SNe.
Abstract
We report the results of James Webb Space Telescope/NIRCam observations of 19 (sub)millimeter sources detected by the Atacama Large Millimeter Array (ALMA). The accurate ALMA positions ...allowed unambiguous identifications of their NIRCam counterparts. Taking gravitational lensing into account, these represent 16 distinct galaxies in three fields and constitute the largest sample of its kind to date. The counterparts’ spectral energy distributions cover from rest-frame ultraviolet to near-IR and provide photometric redshifts (1 <
z
< 4.5) and stellar masses (
M
*
> 10
10.5
M
⊙
), which are similar to submillimeter galaxies (SMGs) studied previously. However, our sample is fainter in (sub)millimeter than the classic SMG samples are, and our sources exhibit a wider range of properties. They have dust-embedded star formation rates as low as 10
M
⊙
yr
−1
, and the sources populate both the star-forming main sequence and the quiescent categories. The deep NIRCam data allow us to study the rest-frame near-IR morphologies. Excluding two multiply imaged systems and one quasar, the majority of the remaining sources are disk-like and show either little or no disturbance. This suggests that secular growth is a potential route for the assembly of high-mass disk galaxies. While a few objects have large disks, the majority have small disks (median half-mass radius of 1.6 kpc). At this time, it is unclear whether this is due to the prevalence of small disks at these redshifts or some unknown selection effects of deep ALMA observations. A larger sample of ALMA sources with NIRCam observations will be able to address this question.
