ABSTRACT We investigate the physical conditions of ionized gas in high-z star-forming galaxies using diagnostic diagrams based on the rest-frame optical emission lines. The sample consists of 701 ...galaxies with an H detection at , from the Fiber Multi-Object Spectrograph (FMOS)-COSMOS survey, that represent the normal star-forming population over the stellar mass range , with those at being well sampled. We confirm an offset of the average location of star-forming galaxies in the Baldwin-Phillips-Terlevich (BPT) diagram ( versus ), primarily toward higher , compared with local galaxies. Based on the S ii ratio, we measure an electron density ( ), which is higher than that of local galaxies. Based on comparisons to theoretical models, we argue that changes in emission-line ratios, including the offset in the BPT diagram, are caused by a higher ionization parameter both at fixed stellar mass and at fixed metallicity, with additional contributions from a higher gas density and possibly a hardening of the ionizing radiation field. Ionization due to active galactic nuclei is ruled out as assessed with Chandra. As a consequence, we revisit the mass-metallicity relation using and a new calibration including as recently introduced by Dopita et al. Consistent with our previous results, the most massive galaxies ( ) are fully enriched, while those at lower masses have metallicities lower than local galaxies. Finally, we demonstrate that the stellar masses, metallicities, and star formation rates of the FMOS sample are well fit with a physically motivated model for the chemical evolution of star-forming galaxies.
Himawari‐8, a next‐generation geostationary meteorological satellite, was launched on 7 October 2014 and became operational on 7 July 2015. The advanced imager on board Himawari‐8 is equipped with 16 ...observational bands (including three visible and three near‐infrared bands) that enable retrieval of full‐disk aerosol optical properties at 10 min intervals from geostationary (GEO) orbit. Here we show the first application of aerosol optical properties (AOPs) derived from Himawari‐8 data to aerosol data assimilation. Validation of the assimilation experiment by comparison with independent observations demonstrated successful modeling of continental pollution that was not predicted by simulation without assimilation and reduced overestimates of dust front concentrations. These promising results suggest that AOPs derived from Himawari‐8/9 and other planned GEO satellites will considerably improve forecasts of air quality, inverse modeling of emissions, and aerosol reanalysis through assimilation techniques.
Key Points
Next‐generation geostationary meteorological satellite Himawari‐8 launched on 7 October 2014
Himawari‐8 provides full‐disk aerosol optical properties at 10 min intervals from geostationary orbit
Promising results of aerosol assimilation experiment on Himawari‐8 retrievals
The mass-metallicity relation (MZR) of type-2 active galactic nuclei (AGNs) at 1.2 < z < 4.0 is investigated by using high-z radio galaxies (HzRGs) and X-ray selected radio-quiet AGNs. We combine new ...rest-frame ultraviolet (UV) spectra of two radio-quiet type-2 AGNs obtained with FOCAS on the Subaru Telescope with existing rest-frame UV emission lines, i.e., C IVλ1549, He IIλ1640, and C IIIλ1909, of a sample of 16 HzRGs and 6 additional X-ray selected type-2 AGNs, whose host stellar masses have been estimated in literature. We divided our sample in three stellar mass bins and calculated averaged emission-line flux ratios of C IVλ1549/He IIλ1640 and C IIIλ1909/C IVλ1549. Comparing observed emission-line flux ratios with photoionization model predictions, we estimated narrow line region (NLR) metallicities for each mass bin. We found that there is a positive correlation between NLR metallicities and stellar masses of type-2 AGNs at z ~ 3. This is the first indication that AGN metallicities are related to their hosts, i.e., stellar mass. Since NLR metallicities and stellar masses follow a similar relation as the MZR in star-forming galaxies at similar redshifts, our results indicate that NLR metallicities are related to those of the host galaxies. This study highlights the importance of considering lower-mass X-ray selected AGNs in addition to radio galaxies to explore the metallicity properties of NLRs at high redshift.
ABSTRACT We aim to search for hyperluminous infrared (IR) galaxies (HyLIRGs) with IR luminosity > 1013 L☉ by applying the selection method of dust-obscured galaxies (DOGs). They are spatially rare ...but could correspond to a maximum phase of cosmic star formation (SF) and/or active galactic nucleus (AGN) activity; hence, they are a crucial population for understanding the SF and mass assembly history of galaxies. Combining the optical and IR catalogs obtained from the Sloan Digital Sky Survey (SDSS) and Wide-field Infrared Survey Explorer (WISE), we performed the extensive HyLIRGs survey; we selected 5311 IR-bright DOGs with i − 22 > 7.0 and flux at 22 m > 3.8 mJy in 14,555 deg2, where i and 22 are i-band and 22 m AB magnitudes, respectively. Among them, 67 DOGs have reliable spectroscopic redshifts that enable us to estimate their total IR luminosity based on the spectral energy distribution fitting. Consequently, we successfully discovered 24 HyLIRGs among the 67 spectroscopically confirmed DOGs. We found that (i) i − 22 color of IR-bright DOGs correlates with the total IR luminosity and (ii) the surface number density of HyLIRGs is >0.17 deg−2. A large fraction (∼73%) of IR-bright DOGs with i − 22 > 7.5 show > 1013 L☉, and the DOG criterion we adopted could be independently effective against the "W1W2-dropout method," based on four WISE bands, for searching hyperluminous IR populations of galaxies.
Generally the gas metallicity in distant galaxies can only be inferred by using a few prominent emission lines. Various theoretical models have been used to predict the relationship between emission ...line fluxes and metallicity, suggesting that some line ratios can be used as diagnostics of the gas metallicity in galaxies. However, accurate empirical calibrations of these emission line flux ratios from real galaxy spectra spanning a wide metallicity range are still lacking. In this paper we provide such empirical calibrations by using the combination of two sets of spectroscopic data: one consisting of low-metallicity galaxies with a measurement of Oiiiλ4363 taken from the literature, including spectra from the Sloan Digital Sky Survey (SDSS), and the other one consisting of galaxies in the SDSS database whose gas metallicity has been determined from various strong emission lines in their spectra. This combined data set constitutes the largest sample of galaxies with information on the gas metallicity available so far and spanning the widest metallicity range. By using these data we obtain accurate empirical relations between gas metallicity and several emission line diagnostics, including the R23 parameter, the Niiλ6584/Hα and Oiiiλ5007/Niiλ6584 ratios. Our empirical diagrams show that the line ratio Oiiiλ5007/Oiiλ3727 is a useful tool to break the degeneracy in the R23 parameter when no information on the Niiλ6584 line is available. The line ratio Neiiiλ3869/Oiiλ3727 also results to be a useful metallicity indicator for high-z galaxies, especially when the R23 parameter or other diagnostics involving Oiiiλ5007 or Niiλ6584 are not available. Additional, useful diagnostics newly proposed in this paper are the line ratios of (Hα+Nii$\lambda\lambda$6548,6584)/Siiλ6720, Oiiiλ5007/Hβ, and Oiiλ3727/Hβ. Finally, we compare these empirical relations with photoionization models. We find that the empirical R23-metallicity sequence is strongly discrepant with respect to the trend expected by models with constant ionization parameter. Such a discrepancy is also found for other line ratios. These discrepancies provide evidence for a strong metallicity dependence of the average ionization parameter in galaxies. In particular, we find that the average ionization parameter in galaxies increases by ~0.7 dex as the metallicity decreases from 2 $Z_{\odot}$ to 0.05 $Z_{\odot}$, with a small dispersion. This result should warn about the use of theoretical models with constant ionization parameter to infer metallicities from observed line ratios.
ABSTRACT
Type II supernovae (SNe) interacting with disc-like circumstellar matter (CSM) have been suggested as an explanation of some unusual Type II SNe, e.g. the so-called impossible SN, iPTF14hls. ...There are some radiation hydrodynamic simulations for such SNe interacting with a CSM disc. However, such disc interaction models so far have not included the effect of the ionization and recombination processes in the SN ejecta, i.e. the fact that the photosphere of Type IIP SNe between ∼10 and ∼100 d is regulated by the hydrogen recombination front. We calculate light curves for Type IIP SNe interacting with a CSM disc viewed from the polar direction, and examine the effects of the disc density and opening angle on their bolometric light curves. This work embeds the shock interaction model of Moriya et al. within the Type IIP SN model of Kasen & Woosley, for taking into account the effects of the ionization and recombination in the SN ejecta. We demonstrate that such interacting SNe show three phases with different photometric and spectroscopic properties, following the change in the energy source: First few tens of days after explosion (phase 1), ∼10 to ∼100 d (phase 2), and days after that (phase 3). From the calculations, we conclude that such hidden CSM disc cannot account for overluminous Type IIP SNe. We find that the luminosity ratio between phase 1 and phase 2 has information on the opening angle of the CSM disc. We thus encourage early photometric and spectroscopic observations of interacting SNe for investigating their CSM geometry.
Based on 5344 quasar spectra taken from the SDSS Data Release 2, the dependences of various emission-line flux ratios on redshift and quasar luminosity are investigated in the ranges $2.0 \leq z \leq ...4.5$ and $-24.5 \geq M_B \geq -29.5$. We show that the emission lines in the composite spectra are fitted better with power-law profiles than with double Gaussian or modified Lorentzian profiles, and in particular we show that the power-law profiles are more appropriate to measure broad emission-line fluxes than other methods. The composite spectra show that there are statistically significant correlations between quasar luminosity and various emission-line flux ratios, such as Nv/Civ and Nv/Heii, while there are only marginal correlations between quasar redshift and emission-line flux ratios. We obtain detailed photoionization models to interpret the observed line ratios. The correlation of line ratios with luminosity is interpreted in terms of higher gas metallicity in more luminous quasars. For a given quasar luminosity, there is no metallicity evolution for the redshift range $2.0 \leq z \leq 4.5$. The typical metallicity of BLR gas clouds is estimated to be $Z \sim 5~ Z_\odot$, although the inferred metallicity depends on the assumed BLR cloud properties, such as their density distribution function and their radial distribution. The absence of a metallicity evolution up to $z \sim 4.5$ implies that the active star-formation epoch of quasar host galaxies occurred at $z \ga 7$.
We investigated the interstellar medium (ISM) properties of the disc and outflowing gas in the central regions of nine nearby Seyfert galaxies, all characterised by prominent conical or biconical ...outflows. These objects are part of the Measuring Active Galactic Nuclei Under MUSE Microscope (MAGNUM) survey, which aims to probe their physical conditions and ionisation mechanism by exploiting the unprecedented sensitivity of the Multi Unit Spectroscopic Explorer (MUSE), combined with its spatial and spectral coverage. Specifically, we studied the different properties of the gas in the disc and in the outflow with spatially and kinematically resolved maps by dividing the strongest emission lines in velocity bins. We associated the core of the lines with the disc, consistent with the stellar velocity, and the redshifted and the blueshifted wings with the outflow. We measured the reddening, density, ionisation parameter, and dominant ionisation source of the emitting gas for both components in each galaxy. We find that the outflowing gas is characterised by higher values of density and ionisation parameter than the disc, which presents a higher dust extinction. Moreover, we distinguish high- and low-ionisation regions across the portion of spatially resolved narrow-line region (NLR) traced by the outflowing gas. The high-ionisation regions characterised by the lowest N II/Hα and S II/Hα line ratios generally trace the innermost parts along the axis of the emitting cones where the S III/S II line ratio is enhanced, while the low-ionisation regions follow the cone edges and/or the regions perpendicular to the axis of the outflows, also characterised by a higher O III velocity dispersion. A possible scenario to explain these features relies on the presence of two distinct populations of line emitting clouds: one is optically thin to the radiation and is characterised by the highest excitation, while the other is optically thick and is impinged by a filtered, and thus harder, radiation field which generates strong low-excitation lines. The highest values of N II/Hα and S II/Hα line ratios may be due to shocks and/or a hard filtered radiation field from the active galactic nucleus.
There is no standard first-line chemotherapy for recurrent/metastatic (RM) or unresectable locally advanced (LA) salivary gland carcinoma (SGC).
We conducted a single institution, open-label, single ...arm, phase II trial of combined androgen blockade (CAB) for androgen receptor (AR)-positive SGC. Leuprorelin acetate was administered subcutaneously at a dose of 3.75mg every 4weeks. Bicalutamide was administered orally at a daily dose of 80mg. Patients were treated until progressive disease or unacceptable toxicities.
Thirty-six eligible patients were enrolled. Thirty-three patients had RM disease and three patients had LA disease. The pathological diagnoses were salivary duct carcinoma (34 patients, 94%) and adenocarcinoma, NOS (two patients, 6%). The best overall response rate was 41.7% n=15, 95% confidence interval (CI), 25.5%–59.2%, the clinical benefit rate was 75.0% (n=27, 95% CI, 57.8%–87.9%). The median progression-free survival was 8.8months (95% CI, 6.3–12.3months) and the median overall survival was 30.5months (95% CI, 16.8months to not reached). Additional analyses between treatment outcomes and clinicopathological factors or biomarkers including AR positivity, human epidermal growth factor receptor 2 status, and its complex downstream signaling pathway gene mutations showed no statistically significant differences. Elevated grade 3 liver transaminases and increased serum creatinine were reported in two patients, respectively. Discontinuation of leuprorelin acetate or bicalutamide due to adverse event occurred in one patient.
This study suggests that CAB has equivalent efficacy and less toxicity for patients with AR-positive RM or unresectable LA SGC compared with conventional chemotherapy, which warrants further study.
UMIN-CTR (http://www.umin.ac.jp/ctr/index-j.htm), identification number: UMIN000005703
While major mergers have long been proposed as a driver of both active galactic nucleus (AGN) activity and the relation, studies of moderate to high-redshift Seyfert-luminosity AGN hosts have found ...little evidence for enhanced rates of interactions. However, both theory and observation suggest that while these AGNs may be fueled by stochastic accretion and secular processes, high-luminosity, high-redshift, and heavily obscured AGNs are the AGNs most likely to be merger-driven. To better sample this population of AGNs, we turn to infrared selection in the CANDELS/COSMOS field. Compared to their lower-luminosity and less obscured X-ray-only counterparts, IR-only AGNs (luminous, heavily obscured AGNs) are more likely to be classified as either irregular ( versus ) or asymmetric ( versus ) and are less likely to have a spheroidal component ( versus ). Furthermore, IR-only AGNs are also significantly more likely than X-ray-only AGNs ( versus ) to be classified either as interacting or merging in a way that significantly disturbs the host galaxy or as disturbed, though not clearly interacting or merging, which potentially represents the late stages of a major merger. This suggests that while major mergers may not contribute significantly to the fueling of Seyfert-luminosity AGNs, interactions appear to play a more dominant role in the triggering and fueling of high-luminosity heavily obscured AGNs.
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