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.
We present 8.5 arcsec resolution 1.1-mm continuum imaging and CO spectroscopic redshift measurements of eight extremely bright submillimetre galaxies identified from the Planck and Herschel surveys, ...taken with the Large Millimeter Telescope's AzTEC and Redshift Search Receiver instruments. We compiled a candidate list of high-redshift galaxies by cross-correlating the Planck Surveyor mission's highest frequency channel (857 GHz, full width at half-maximum = 4.5 arcmin) with the archival Herschel Spectral and Photometric Imaging Receiver imaging data, and requiring the presence of a unique, single Herschel counterpart within the 150-arcsec search radius of the Planck source positions with 350-μm flux density larger than 100 mJy, excluding known blazars and foreground galaxies. All eight candidate objects observed are detected in 1.1 mm continuum by AzTEC bolometer camera, and at least one CO line is detected in all cases with a spectroscopic redshift between 1.3 < z
CO < 3.3. Their infrared (IR) spectral energy distributions (SEDs) mapped using the Herschel and AzTEC photometry are consistent with cold dust emission with characteristic temperature between T
d = 43 and 84 K. With apparent IR luminosity of up to L
IR = 3 × 1014μ−1 L⊙, they are some of the most luminous galaxies ever found (with yet unknown gravitational magnification factor μ). The analysis of their SEDs suggests that star formation is powering the bulk of their extremely large IR luminosities. Derived molecular gas masses of
$M_{\rm {H_2}}=(0.6{\rm -}7.8)\times 10^{11} \,\mathrm{M}_{\odot }$
(for μ ≈ 10) also make them some of the most gas-rich high-redshift galaxies ever detected.
ABSTRACT We report the detection of two CH3OH lines (JK = 2K-1K and 3K-2K) between the progenitor's disks ("Overlap") of the mid-stage merging galaxy VV 114 obtained using the Atacama Large ...Millimeter/submillimeter Array (ALMA) Band 3 and Band 4. The detected CH3OH emission shows an extended filamentary structure (∼3 kpc) across the progenitor's disks with relatively large velocity width (FWZI ∼ 150 km s−1). The emission is only significant in the "overlap" and not detected in the two merging nuclei. Assuming optically thin emission and local thermodynamic equilibrium, we found the CH3OH column density relative to H2 ( ) peaks at the "Overlap" (∼8 × 10−9), which is almost an order of magnitude larger than that at the eastern nucleus. We suggest that kpc-scale shocks driven by galaxy-galaxy collision may play an important role to enhance the CH3OH abundance at the "Overlap." This scenario is consistent with shock-induced large velocity dispersion components of ionized gas that have been detected in optical wavelength at the same region. Conversely, low at the nuclear regions might be attributed to the strong photodissociation by nuclear starbursts and/or a putative active galactic nucleus, or inefficient production of CH3OH on dust grains due to initial high-temperature conditions (i.e., desorption of the precursor molecule, CO, into gas phase before forming CH3OH on dust grains). These ALMA observations demonstrate that CH3OH is a unique tool to address kpc-scale shock-induced gas dynamics and star formation in merging galaxies.
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 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 present a high-sensitivity (1
σ
< 1.6 mJy beam
−1
) continuum observation in a 343 arcmin
2
area of the northeast region of the Small Magellanic Cloud at a wavelength of 1.1 mm, ...conducted using the AzTEC instrument on the ASTE telescope. In the observed region, we identified 20 objects by contouring 10
σ
emission. Through spectral energy distribution analysis using 1.1 mm,
Herschel
, and
Spitzer
data, we estimated gas masses of 5 × 10
3
–7 × 10
4
M
⊙
, assuming a gas-to-dust ratio of 1000. The dust temperature and index of emissivity were also estimated as 18–33 K and 0.9–1.9, respectively, which are consistent with previous low-resolution studies. The dust temperature and the index of emissivity shows a weak negative linear correlation. We also investigated five CO-detected, dust-selected clouds in detail. The total gas masses were comparable to those estimated from the Mopra CO data, indicating that the assumed gas-to-dust ratio of 1000 and the
X
CO
factor of 1 × 10
21
cm
−2
(K km s
−1
)
−1
, with uncertainties of a factor of 2, are reliable for the estimation of the gas masses of molecular or dust-selected clouds. The dust column density showed good spatial correlation with CO emission, except for an object associated with bright young stellar objects. The 8
μ
m filamentary and clumpy structures also showed a spatial distribution similar to that of the CO emission and dust column density, supporting the fact that polycyclic aromatic hydrocarbon emissions arise from the surfaces of dense gas and dust clouds.
We present the detailed characterization of two extremely red submillimeter galaxies (SMGs), ASXDF1100.053.1 and 231.1, with the Atacama Large Millimeter/submillimeter Array (ALMA) and the Jansky ...Very Large Array. These SMGs were originally selected using AzTEC at 1100 m, and are observed by Herschel to be faint at 100-500 m. Their (sub)millimeter colors are as red as-or redder-than known z 5 SMGs; indeed, ASXDF1100.053.1 is redder than HFLS 3, which lies at z = 6.3. They are also faint and red in the near-/mid-infrared: ∼1 Jy at IRAC 4.5 m and <0.2 Jy in the Ks filter. These SMGs are also faint in the radio waveband, where F6GHz = 4.5 Jy for ASXDF1100.053.1 and F1.4GHz = 28 Jy for ASXDF1100.231.1, suggestive of and for ASXDF1100.053.1 and 231.1, respectively. ASXDF1100.231.1 has a flux excess in the 3.6 m filter, probably due to H emission at z = 4-5. Derived properties of ASXDF1100.053.1 for z = 5.5-7.5 and 231.1 for z = 3.5-5.5 are as follows: their infrared luminosities are 6.5 − 7.4 × 1012 and 4.2-4.5 × 1012 L ; their stellar masses are 0.9-2 × 1011 and 0.4-3 × 1010 M ; their circularized half-light radii in the ALMA maps are ∼1 and 0.2 kpc (∼2-3 kpc for 90% of the total flux). Last, their surface infrared luminosity densities, IR, are ∼1 × 1012 and 1.5 × 1013 L kpc−2, similar to values seen for local (U)LIRGs. These data suggest that ASXDF1100.053.1 and 231.1 are compact SMGs at z 4 and can plausibly evolve into z 3 compact quiescent galaxies.
We present high-resolution (1 0) Atacama Large Millimeter/submillimeter Array (ALMA) observations of CO (1-0) and CO (2-1) rotational transitions toward the nearby IR-luminous merger NGC 1614 ...supplemented with ALMA archival data of CO (3-2) and CO (6-5) transitions. The CO (6-5) emission arises from the starburst ring (central 590 pc in radius), while the lower-J CO lines are distributed over the outer disk (∼3.3 kpc in radius). Radiative transfer and photon-dominated region (PDR) modeling reveals that the starburst ring has a single warmer gas component with more a intense far-ultraviolet radiation field ( cm−3, K, and ) relative to the outer disk ( cm−3, K, and ). A two-phase molecular interstellar medium with a warm and cold (>70 and ∼19 K) component is also an applicable model for the starburst ring. A possible source for heating the warm gas component is mechanical heating due to stellar feedback rather than PDR. Furthermore, we find evidence for non-circular motions along the north-south optical bar in the lower-J CO images, suggesting a cold gas inflow. We suggest that star formation in the starburst ring is sustained by the bar-driven cold gas inflow and that starburst activities radiatively and mechanically power the CO excitation. The absence of a bright active galactic nucleus can be explained by a scenario where cold gas accumulating on the starburst ring is exhausted as the fuel for star formation or is launched as an outflow before being able to feed to the nucleus.
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