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Observed trends in tropospheric ozone, an important air pollutant and short‐lived climate forcer (SLCF), are estimated using available surface and ozonesonde profile data for 1993–2019, using a coherent methodology, and compared to modeled trends (1995–2015) from the Arctic Monitoring Assessment Program SLCF 2021 assessment. Increases in observed surface ozone at Arctic coastal sites, notably during winter, and concurrent decreasing trends in surface carbon monoxide, are generally captured by multi‐model median trends. Wintertime increases are also estimated in the free troposphere at most Arctic sites, with decreases during spring months. Winter trends tend to be overestimated by the multi‐model medians. Springtime surface ozone increases in northern coastal Alaska are not simulated while negative springtime trends in northern Scandinavia are not always reproduced. Possible reasons for observed changes and model performance are discussed including decreasing precursor emissions, changing ozone dry deposition, and variability in large‐scale meteorology. Plain Language Summary: The Arctic is warming much faster than the rest of the globe due to increases in carbon dioxide, and other trace constituents like ozone, also an air pollutant. However, improved understanding is needed about long‐term changes or trends in Arctic tropospheric ozone. A coherent methodology is used to identify trends in surface and regular profile measurements over the last 20–30 years, and results from six chemistry‐climate models. Increases in observed ozone are found at the surface and in the free troposphere during winter in the high Arctic. Paradoxically, decreases in nitrogen oxide emissions at mid‐latitudes appear to be leading to increases in ozone during winter, but associated increases in Arctic tropospheric ozone tend to be overestimated in the models. Increases are also found at the surface in northern Alaska during spring but not reproduced by the models. The causes are unknown but could be related to changes in local sources or sinks of Arctic ozone or in large‐scale weather patterns. Declining mid‐latitude emissions, or increased dry deposition to northern forests, may explain negative surface ozone trends over northern Scandinavia in spring that are not always captured by the models. Further work is needed to understand changes in Arctic tropospheric ozone. Key Points: Coherent ozone trend analysis methodology applied to multi‐decade, pan‐Arctic surface and ozonesonde datasets and multi‐model mediansIncreasing winter Arctic tropospheric ozone overestimated by models in the free troposphere, and spring surface changes not capturedSpring (summer) decreases (increases) in observed ozone throughout the troposphere, not always simulated by models [ABSTRACT FROM AUTHOR]

The currently used standardization of Type Ia supernovae results in Hubble residuals whose physical origin is unaccounted for. Here, we present a complete physical interpretation of the Hubble residuals based on a novel Bayesian hierarchical model of Type Ia supernovae in which latent variables describing intrinsic and extrinsic (dust related) supernova properties originate from two supernova populations. Fitting the model to SALT2 light-curve parameters of supernovae in the Hubble flow we find strong (4σ) evidence for the presence of two overlapping, but distinct, populations differentiated primarily by their mean SALT2 shape parameter (stretch) x 1. Supernovae from the population with predominantly slow decliners (higher average x 1) are found to be intrinsically bluer (mean SALT2 colour c ≈ −0.11) and twice as reddened by dust (mean reddening E (B − V) ≈ 0.10) than those from the other population which is dominated by fast decliners (lower average x 1) with c ≈ −0.04 and E (B − V) ≈ 0.05. The inferred extinction coefficient R B in both supernova populations follows a broad distribution (scatter 0.9) with a mean of 4.1, which coincides closely with the value associated with mean extinction law in the Milky Way. We also find that the supernova data favour a peaked (two-tailed) distribution of selective extinction E (B − V) over the commonly adopted exponential model. Our approach provides a complete explanation of the distribution of supernova light-curve parameters in terms of extinction properties and the above-mentioned differences between the two populations, without the need for introducing any intrinsic scatter. [ABSTRACT FROM AUTHOR]

We reanalyse observations of Type Ia supernovae (SNe) and Cepheids used in the local determination of the Hubble constant and find strong evidence that SN standardization in the calibration sample (galaxies with observed Cepheids) requires a steeper slope of the colour correction than in the cosmological sample (galaxies in the Hubble flow). The colour correction in the calibration sample is consistent with being entirely due to an extinction correction due to dust with properties similar to those of the Milky Way (R B ≈ 4.6 ± 0.4) and there is no evidence for intrinsic scatter in the SN peak magnitudes. An immediate consequence of this finding is that the local measurement of the Hubble constant becomes dependent on the choice of SN reference colour, i.e. the colour of an unreddened SN. Specifically, the Hubble constant inferred from the same observations decreases gradually with the reference colour assumed in the SN standardization. We recover the Hubble constant measured by SH0ES for the standard choice of reference colour (SALT2 colour parameter c  = 0), while for a reference colour that coincides with the blue end of the observed SN colour distribution (c ≈ −0.13), the Hubble constant from Planck observations of the cosmic microwave background (CMB) [assuming a flat Lambda cold dark matter (ΛCDM) cosmological model] is recovered. These results are intriguing in that they may provide an avenue for resolving the Hubble tension. However, since there is no obvious physical basis for the differences in colour corrections in the two SN samples, the origin of these requires further investigation. [ABSTRACT FROM AUTHOR]

Strongly lensed supernovae (SNe) can be detected as multiply imaged or highly magnified transients. In order to compare the performances of these two observational strategies, we calculate expected discovery rates as a function of survey depth in five grizy filters and for different classes of SNe (types Ia, IIP, IIL, Ibc, and IIn). We find that detections via magnification is the only effective strategy for relatively shallow pre-LSST (Large Synoptic Sky Survey) surveys. For survey depths about the LSST capacity, both strategies yield comparable numbers of lensed SNe. SN samples from the two methods are to a large extent independent and combining them increases detection rates by about 50 per cent. While the number of lensed SNe detectable via magnification saturates at the limiting magnitudes of LSST, detection rates of multiply imaged SN still go up drastically at increasing survey depth. Comparing potential discovery spaces, we find that lensed SNe found via image multiplicity exhibit longer time delays and larger image separations making them more suitable for cosmological constraints than their counterparts found via magnification. We provide useful fitting functions approximating the computed discovery rates for different SN classes and detection methods. We find that the Zwicky Transient Factory will find about two type Ia and four core-collapse lensed SNe per year at a limiting magnitude of 20.6 in the r band. Applying a hybrid method which combines searching for highly magnified or multiply imaged transients, we find that LSST will detect 89 type Ia and 254 core-collapse lensed SNe per year. In all cases, lensed core-collapsed SNe will be dominated by type IIn SNe contributing to 80 per cent of the total counts, although this prediction relies quite strongly on the adopted spectral templates for this class of SNe. Revisiting the case of the lensed SN iPTF16geu, we find that it is consistent within the 2σ contours of predicted redshifts and magnifications for the intermediate Palomar Transient Factory survey. [ABSTRACT FROM AUTHOR]

The physical characteristics of dust formed in supernovae is poorly known. In this paper, we investigate the extinction properties of dust formed in the type IIn SN 2005ip. The observed light curves of SN 2005ip all exhibit a sudden drop around 50 days after discovery. This has been attributed to dust formation in the dense circumstellar medium. We modeled the intrinsic light curves in six optical bands, adopting a theoretical model for the luminosity evolution of supernovae interacting with their circumstellar material. From the difference between the observed and intrinsic light curves, we calculated extinction curves as a function of time. The total-to-selective extinction ratio, RV , was determined from the extinction in the B and V bands. The resulting extinction, AV , increases monotonically up to about 1 mag, 150 days after discovery. The inferred RV value also increases slightly with time, but appears constant in the range 4.5-8, beyond 100 days after discovery. The analysis confirms that dust is likely formed in SN 2005ip, starting about two months after explosion. The high value of RV , that is, gray dust, suggests dust properties different from the Milky Way. While this result hinges on the assumed theoretical intrinsic light curve evolution, it is encouraging that the fitted light curves are as expected for standard ejecta and circumstellar medium density structures. [ABSTRACT FROM AUTHOR]

We investigate the stellar-mass Tully-Fisher relation (TFR) between the stellar mass and the integrated gas velocity dispersion, quantified by the kinematic estimator S0.5 measured from strong emission lines in spectra of galaxies at 0 < z < 5. We combine luminosity-selected galaxies ('high-luminosity sample') with galaxies selected in other ways ('low-luminosity sample') to cover a range in stellar mass that spans almost five orders of magnitude: 7.0 ≲logM*/M☉ ≲11.5. We find that the logarithmic power-law slope and normalization of the TFR are independent of redshift out to z∼3. The scatter in the TFR is <0.5 dex such that the gas velocity dispersion can be used as a proxy for the stellar mass of a galaxy independently of its redshift. At z>3, the scatter increases and the existence of a correlation is not obvious. The high-luminosity sample exhibits a flatter slope of 1.5 ± 0.2 at z < 3 compared to the lowluminosity sample slope of 2.9 ± 0.3, suggesting a turnover in the TFR. The combined sample is well fit with a break in the TFR at a characteristic stellar-mass scale of M*± 1010M☉, with no significant evolution out to z∼3. We demonstrate that a break in the TFR with a steeper slope at the low-mass end is a natural consequence of galaxy models with a mass-dependent stellar-to-halo mass ratio. [ABSTRACT FROM AUTHOR]

We present new Jansky Very Large Array observations of five pre-Swift gamma-ray bursts for which an ultraluminous [star formation rate (SFR) >100 M⊙ yr-1] dusty host galaxy had previously been inferred from radio or submillimetre observations taken within a few years after the burst. In four of the five cases, we no longer detect any source at the host location to limits much fainter than the original observations, ruling out the existence of an ultraluminous galaxy hosting any of these gamma-ray bursts (GRBs). We continue to detect a source at the position of GRB 980703, but it is much fainter than it was a decade ago and the inferred radio SFR (~80 M⊙) is relatively modest. The radio flattening at 200-1000 d observed in the light curve of this GRB may have been caused by a decelerating counterjet oriented 180 deg away from the viewer, although an unjetted wind model can also explain the data. Our results eliminate all well-established ultraluminous infrared galaxies (ULIRGs) among the pre-Swift host population. They also rule out all cases for which an unobscured GRB was found in a galaxy dominated by heavily obscured star formation. When GRBs do occur in ULIRGs, the afterglow is almost always observed to be heavily obscured, consistent with the large dust opacities and high dust covering fractions characteristic of these systems. [ABSTRACT FROM AUTHOR]

The origin of dust in galaxies is still a mystery. The majority of the refractory elements are produced in supernova explosions, but it is unclear how and where dust grains condense and grow, and how they avoid destruction in the harsh environments of star-forming galaxies. The recent detection of 0.1 to 0.5 solar masses of dust in nearby supernova remnants suggests in situ dust formation, while other observations reveal very little dust in supernovae in the first few years after explosion. Observations of the spectral evolution of the bright SN 2010jl have been interpreted as pre-existing dust, dust formation or no dust at all. Here we report the rapid (40 to 240 days) formation of dust in its dense circumstellar medium. The wavelength-dependent extinction of this dust reveals the presence of very large (exceeding one micrometre) grains, which resist destruction. At later times (500 to 900 days), the near-infrared thermal emission shows an accelerated growth in dust mass, marking the transition of the dust source from the circumstellar medium to the ejecta. This provides the link between the early and late dust mass evolution in supernovae with dense circumstellar media. [ABSTRACT FROM AUTHOR]

It has been shown in previous work that DARKexp, which is a theoretically derived, maximum entropy, one shape parameter model for isotropic collisionless systems, provides very good fits to simulated and observed dark matter halos. Specifically, it fits the energy distribution, N(E), and the density profiles, including the central cusp. Here, we extend DARKexp N(E) to include the distribution in angular momentum, L2, for spherically symmetric systems. First, we argue, based on theoretical, semi-analytical, and simulation results, that while dark matter halos are relaxed in energy, they are not nearly as relaxed in angular momentum, which precludes using maximum entropy to uniquely derive N(E, L2). Instead, we require that when integrating N(E, L2) over squared angular momenta one retrieves the DARKexp N(E). Starting with a general expression for N(E, L2) we show how the distribution of particles in L2 is related to the shape of the velocity distribution function, VDF, and velocity anisotropy profile, β(r). We then demonstrate that astrophysically realistic halos, as judged by the VDF shape and β(r), must have linear or convex distributions in L2, for each separate energy bin. The distribution in energy of the most bound particles must be nearly flat, and become more tilted in favor of radial orbits for less bound particles. These results are consistent with numerical simulations and represent an important step toward deriving the full distribution function for spherically symmetric dark matter halos. [ABSTRACT FROM AUTHOR]

Unusual extinction curves of high-redshift QSOs have been taken as evidence that dust is primarily produced by supernovae at high redshift. In particular, the 3000Å Todini-Ferrara-Maiolino kink in the extinction curve of the z = 6.20 SDSS J1048+4637 has been attributed to supernova dust. Here we discuss the challenges in inferring robust extinction curves of high-redshift QSOs and critically assess previous claims of detection of supernova dust. In particular, we address the sensitivity to the choice of intrinsic QSO spectrum, the need for a long wavelength baseline, and the drawbacks in fitting theoretical extinction curves. In a sample of 21 QSOs at z ~ 6 we detect significant ultraviolet extinction using existing broadband optical, near-infrared, and Spitzer photometry. The median extinction curve is consistent with a Small Magellanic Cloud curve with A1450 ~ 0.7 mag and does not exhibit any conspicuous (rest frame) 2175Å or 3000Å features. For two QSOs, SDSS J1044-0125 at z = 5.78 and SDSS J1030+0524 at z = 6.31, we further present X-shooter spectra covering the wavelength range 0.9-2.5μm. The resulting non-parametric extinction curves do not exhibit the 3000Å kink. Finally, in a re-analysis of literature spectra of SDSS J1048+4637, we do not find evidence for a conspicuous kink. We conclude that the existing evidence for a 3000Å feature is weak and that the overall dust properties at high and low redshifts show no significant differences. This, however, does not preclude supernovae from dominating the dust budget at high redshift. [ABSTRACT FROM AUTHOR]

The article discusses the gas-phase chemistry of dimethyl sulphide (DMS) and dimethyl sulfoxide and their important oxidation products. The authors also describe the reactions of DMS and dimethyl sulfoxide with OH and NO3 radicals and with halogen atoms and halogen oxides, multiphase chemistry involved in the atmospheric oxidation of DMS and evidence from field and modeling studies on the role of multiphase reactions in the DMS cycle.

We report the discovery of the afterglow of the X-ray rich, long-duration γ-ray burst GRB 011211 and present evidence for oscillatory behaviour in its early optical light curve. The time-scale of the fluctuations, ∼1 h, is much smaller than the time of the observations, ∼12 h from the onset of the γ-ray burst. The character and strength of the fluctuations are unprecedented and are inconsistent with causally connected variations in the emission of a symmetric, relativistic blast wave, i.e. flux variations which are produced uniformly throughout the shell surface are ruled out. Therefore, the wiggles are the result of spherically asymmetric density or energy variations. Additionally, there is evidence for fluctuations in the X-ray afterglow light curve. If real, the resulting difference in the observed time of the peaks of the short-term variations at X-ray and optical frequencies, would demonstrate that the energy content across the jet-emitting surface is not uniform. [Copyright &y& Elsevier]

Over the past five years evidence has mounted that long-duration (>2 s) γ-ray bursts (GRBs)-the most luminous of all astronomical explosions-signal the collapse of massive stars in our Universe. This evidence was originally based on the probable association of one unusual GRB with a supernova¹, but now includes the association of GRBs with regions of massive star formation in distant galaxies2,3, the appearance of supernova-like 'bumps' in the optical afterglow light curves of several bursts4-6 and lines of freshly synthesized elements in the spectra of a few X-ray afterglows7. These observations support, but do not yet conclusively demonstrate, the idea that long-duration GRBs are associated with the deaths of massive stars, presumably arising from core collapse. Here we report evidence that a very energetic supernova (a hypernova) was temporally and spatially coincident with a GRB at redshift z = 0.1685. The timing of the supernova indicates that it exploded within a few days of the GRB, strongly suggesting that core-collapse events can give rise to GRBs, thereby favouring the 'collapsar' model8,9. [ABSTRACT FROM AUTHOR]

It has long been known that there are two classes of γ-ray bursts (GRBs), mainly distinguished by their durations. The breakthrough in our understanding of long-duration GRBs (those lasting more than ∼2 s), which ultimately linked them with energetic type Ic supernovae, came from the discovery of their long-lived X-ray and optical ‘afterglows’, when precise and rapid localizations of the sources could finally be obtained. X-ray localizations have recently become available for short (duration <2 s) GRBs, which have evaded optical detection for more than 30 years. Here we report the first discovery of transient optical emission (R-band magnitude ∼23) associated with a short burst: GRB 050709. The optical afterglow was localized with subarcsecond accuracy, and lies in the outskirts of a blue dwarf galaxy. The optical and X-ray afterglow properties 34 h after the GRB are reminiscent of the afterglows of long GRBs, which are attributable to synchrotron emission from ultrarelativistic ejecta. We did not, however, detect a supernova, as found in most nearby long GRB afterglows, which suggests a different origin for the short GRBs. [ABSTRACT FROM AUTHOR]

Reports on the measurement of polarization of the optical emission from gamma ray burst (GRB) 990123 with the Nordic Optical Telescope. Findings, including an upper limit of 2.3% on the linear polarization; Provision of important clues to the blast wave geometry and magnetic field structure of GRBs; Indications that an optical afterglow was produced by a blast wave; Suggestion that a collimated jet would solve the problem of energy release in the blast.

In late 2014, four images of supernova (SN) "Refsdal," the first known example of a strongly lensed SN with multiple resolved images, were detected in the MACS J1149 galaxy-cluster field. Following the images' discovery, the SN was predicted to reappear within hundreds of days at a new position ∼8″ away in the field. The observed reappearance in late 2015 makes it possible to carry out Refsdal's original proposal to use a multiply imaged SN to measure the Hubble constant H 0, since the time delay between appearances should vary inversely with H 0. Moreover, the position, brightness, and timing of the reappearance enable a novel test of the blind predictions of galaxy-cluster models, which are typically constrained only by the positions of multiply imaged galaxies. We have developed a new photometry pipeline that uses DOLPHOT to measure the fluxes of the five images of SN Refsdal from difference images. We apply four separate techniques to perform a blind measurement of the relative time delays and magnification ratios between the last image SX and the earlier images S1–S4. We measure the relative time delay of SX–S1 to be 376.0 − 5.5 + 5.6 days and the relative magnification to be 0.30 − 0.3 + 0.5 . This corresponds to a 1.5% precision on the time delay and 17% precision for the magnification ratios and includes uncertainties due to millilensing and microlensing. In an accompanying paper, we place initial and blind constraints on the value of the Hubble constant. [ABSTRACT FROM AUTHOR]

Ultraviolet light from early galaxies is thought to have ionized gas in the intergalactic medium. However, there are few observational constraints on this epoch because of the faintness of those galaxies and the redshift of their optical light into the infrared. We report the observation, in JWST imaging, of a distant galaxy that is magnified by gravitational lensing. JWST spectroscopy of the galaxy, at rest-frame optical wavelengths, detects strong nebular emission lines that are attributable to oxygen and hydrogen. The measured redshift is z = 9.51 ± 0.01, corresponding to 510 million years after the Big Bang. The galaxy has a radius of 16:2þ4:6 -7:2 parsecs, which is substantially more compact than galaxies with equivalent luminosity at z ~ 6 to 8, leading to a high star formation rate surface density. [ABSTRACT FROM AUTHOR]

The article discusses Denmark's YDUN programme, an experimental one-year government research-funding scheme exclusively for women launched in 2014, which was considered sexist and caused a political controversy.

The spectacular success of Type Ia supernovae (SNe Ia) in SN-cosmology is based on the assumption that their photometric and spectroscopic properties are invariant with redshift. However, this fundamental assumption needs to be tested with observations of high-z SNe Ia. To date, the majority of SNe Ia observed at moderate to large redshifts (0.4 ≤ z ≤ 1.0) are faint, and the resultant analyses are based on observations with modest signal-to-noise ratios that impart a degree of ambiguity in their determined properties. In rare cases, however, the Universe offers a helping hand: To date a few SNe Ia have been observed that have had their luminosities magnified by intervening galaxies and galaxy clusters acting as gravitational lenses. In this paper, we present long-slit spectroscopy of the lensed SN Ia 2016geu, which occurred at a redshift of z = 0.409, and was magnified by a factor of ≈55 by a galaxy located at z = 0.216. We compared our spectra, which were obtained a couple of weeks to a couple of months past peak light, with the spectroscopic properties of well-observed, nearby SNe Ia, finding that SN 2016geu's properties are commensurate with those of SNe Ia in the local Universe. Based primarily on the velocity and strength of the Si II λ6355 absorption feature, we find that SN 2016geu can be classified as a high-velocity, high-velocity-gradient and 'corenormal' SN Ia. The strength of various features (measured though their pseudo-equivalent widths) argue against SN 2016geu being a faint, broad-lined, cool or shallow-silicon SN Ia. We conclude that the spectroscopic properties of SN 2016geu imply that it is a normal SN Ia, and when taking previous results by other authors into consideration, there is very little, if any, evolution in the observational properties of SNe Ia up to z ≈ 0.4. [ABSTRACT FROM AUTHOR]

The observed association between supernovae and gamma-ray bursts represents a cornerstone in our understanding of the nature of gamma-ray bursts. The collapsar model provides a theoretical framework for this connection. A key element is the launch of a bipolar jet (seen as a gamma-ray burst). The resulting hot cocoon disrupts the star, whereas the 56Ni produced gives rise to radioactive heating of the ejecta, seen as a supernova. In this discussion paper, I summarize the observational status of the supernova-gamma-ray burst connection in the context of the 'engine' picture of jet-driven supernovae and highlight SN 2012bz/GRB 120422A--with its luminous supernova but intermediate high-energy luminosity--as a possible transition object between low-luminosity and jet gamma-ray bursts. The jet channel for supernova explosions may provide new insights into supernova explosions in general. [ABSTRACT FROM AUTHOR]

We present VLT/X-shooter observations of a high-redshift, Type Ia supernova (SN Ia) host galaxy, discovered with HST/WFC3 as part of the CANDELS Supernova project. The galaxy exhibits strong emission lines of Lyα, [O II], Hβ, [O III], and Hα at z = 1.54992+0.00008–0.00004. From the emission-line fluxes and spectral energy distribution fitting of broadband photometry we rule out activity from an active galactic nucleus and characterize the host galaxy as a young, low-mass, metal-poor, starburst galaxy with low intrinsic extinction and high Lyα escape fraction. The host galaxy stands out in terms of the star formation, stellar mass, and metallicity compared to its lower redshift counterparts, mainly because of its high specific star formation rate. If valid for a larger sample of high-redshift SN Ia host galaxies, such changes in the host galaxy properties with redshift are of interest because of the potential impact on the use of SN Ia as standard candles in cosmology. [ABSTRACT FROM AUTHOR]

Long-duration gamma-ray bursts (GRBs) are powerful tracers of star-forming galaxies. We have defined a homogeneous subsample of 69 Swift GRB-selected galaxies spanning a very wide redshift range. Special attention has been devoted to making the sample optically unbiased through simple and well-defined selection criteria based on the high-energy properties of the bursts and their positions on the sky. Thanks to our extensive follow-up observations, this sample has now achieved a comparatively high degree of redshift completeness, and thus provides a legacy sample, useful for statistical studies of GRBs and their host galaxies. In this paper, we present the survey design and summarize the results of our observing program conducted at the ESO Very Large Telescope (VLT) aimed at obtaining the most basic properties of galaxies in this sample, including a catalog of R and Ks magnitudes and redshifts. We detect the host galaxies for 80% of the GRBs in the sample, although only 42% have Ks-band detections, which confirms that GRB-selected host galaxies are generally blue. The sample is not uniformly blue, however, with two extremely red objects detected. Moreover, galaxies hosting GRBs with no optical/NIR afterglows, whose identification therefore relies on X-ray localizations, are significantly brighter and redder than those with an optical/NIR afterglow. This supports a scenario where GRBs occurring in more massive and dusty galaxies frequently suffer high optical obscuration. Our spectroscopic campaign has resulted in 77% now having redshift measurements, with a median redshift of 2.14 ± 0.18. TOUGH alone includes 17 detected z > 2 Swift GRB host galaxies suitable for individual and statistical studies—a substantial increase over previous samples. Seven hosts have detections of the Lyα emission line and we can exclude an early indication that Lyα emission is ubiquitous among GRB hosts, but confirm that Lyα is stronger in GRB-selected galaxies than in flux-limited samples of Lyman break galaxies. [ABSTRACT FROM AUTHOR]

Smog chamber experiments have been conducted in which cyclic monoterpenes were oxidized in the gas phase by OH. The evolved secondary organic aerosol (SOA) was analyzed by LC-MSn and the gas-phase products were analyzed by FT-IR. The concentrations of the identified compounds corresponded to carbon mass balances in the range of 40%-90%. The identified compounds in the particular phase corresponded to 0.5%-4.2% of the reacted carbon. The most abundant compounds in SOAfrom terpenes with an endocyclic C=C double bond were C10-keto-aldehydes, C10-keto-carboxylic acids, C10-hydroxy-keto-carboxylic acids, and C10-hydroxy-keto-aldehydes (pinonaldehyde, pinonic acid, hydroxy-pinonic acid isomers, and hydroxy-pinonaldehyde isomers from alpha-pinene; 3-caronaldehyde, 3-caronic acid, hydroxy-3-caronic acid isomers, and hydroxy-3-caronaldehyde isomers from 3-carene). The most abundant compounds in SOA from terpenes with an exocyclic C=C double bond were C9-ketones,C9-dicarboxylic acids, and C10-hydroxy-keto-carboxylic acids (nopinone, pinic acid, and hydroxy-pinonic acid isomers from beta -pinene; sabinaketone, sabinic acid and hydroxy-sabinonicacid isomers from sabinene). Decarboxylated analogues of most of thecompounds were present in SOA in minor concentrations, such as C9-keto-carboxylic acids (norpinonic acid, nor-3-caronic acid) and C8-dicarboxylic acids (norpinic acid, nor-3-caric acid, norsabinic acid). In SOA from limonene, which contains an endocyclic as well as an exocyclic C=C double bond, the most abundant compounds were a C10-keto-aldehyde and its oxo-derivative (limononaldehyde and keto-limonon aldehyde) together with hydroxy-derivativesof a C10-keto-carboxylic acid (isomers of hydroxy-limononic acid). Also a C10-keto-carboxylic acid (limononic acid)was present together with minor concentrations of a C9-dicarbox [ABSTRACT FROM AUTHOR]

Context. The Subaru Deep Field (SDF) Supernova Survey discovered ten Type Ia supernovae (SNe Ia) in the redshift range 1:5 < z < 2:0, determined solely from photometric redshifts of the host galaxies. However, photometric redshifts might be biased, and the SN sample could be contaminated by active galactic nuclei (AGNs). Aims. We aim to obtain the first robust redshift measurement and classification of a z > 1.5 SDF SN Ia host galaxy candidate. Methods. We use the X-shooter (U-to-K-band) spectrograph on the Very Large Telescope to allow the detection of different emission lines in a wide spectral range. Results. We measure a spectroscopic redshift of 1.54563 ± 0:00027 of hSDF0705.25, consistent with its photometric redshift of 1.552 ± 0.018. From the strong emission-line spectrum we rule out AGN activity, thereby confirming the optical transient as a SN. The host galaxy follows the fundamental metallicity relation showing that the properties of this high-redshift SN Ia host galaxy is similar to other field galaxies. Conclusions. Spectroscopic confirmation of additional SDF SN hosts would be required to confirm the cosmic SN rate evolution measured in the SDF. [ABSTRACT FROM AUTHOR]

ABSTRACT We present Very Large Telescope/X-shooter spectra of 13 galaxies in the redshift range 1 ≲ z ≲ 6, which are strongly lensed by massive galaxy clusters. Spectroscopic redshifts are measured for nine galaxies, while three sources have redshifts determined from continuum breaks in their spectra. The stellar masses of the galaxies span four orders of magnitude between 107 and 1011 M⊙ and have luminosities at 1500 Å rest frame between 0.004 and 9 L* after correcting for the magnification. This allows us to probe a variety of galaxy types from young, low-mass starburst galaxies to massive evolved galaxies. The lensed galaxies with stellar masses less than 1010 M⊙ have a large scatter compared to the fundamental relation between stellar mass, star formation rates and oxygen abundances. We provide a modified fit to the fundamental relation for low-mass, low-metallicity galaxies with a weaker dependence of the metallicity on either the star formation rate or stellar mass compared to low-redshift, high-mass and high-metallicity Sloan Digital Sky Survey galaxies. [ABSTRACT FROM AUTHOR]

ABSTRACT Since globular clusters (GCs) are old, low- N systems their dynamics is widely believed to be fully dominated by collisional two-body processes and their surface brightness profiles are fitted by King models. However, for many GCs, especially those with Hubble Space Telescope-resolved central regions and 'extratidal' features, King models provide poor fits. We suggest that this is partly because collisionless dynamics is also important and contributes to shaping the cluster properties. We show using time-scale and length-scale arguments that except for the very centres of clusters, collisionless dynamics should be more important than collisional. We then fit 38 GCs analysed by Noyola & Gebhardt with (collisional) King and (collisionless) DARKexp models over the full available radial range, and find that the latter provide a better fit to 29 GCs; for six of these the fit is at least approximately five times better in terms of rms. DARKexp models are theoretically derived maximum entropy equilibrium states of self-gravitating collisionless systems and have already been shown to fit the results of dark matter N-body simulations. (We do not attempt fits with ad hoc fitting functions.) [ABSTRACT FROM AUTHOR]

Examines the mechanism of the gas-phase nitration of phenol on the aqueous-phase formation of nitrophenols. Reaction between nitrate and phenol; Influence of ozone on the yield of 4-nitrophenol isomer; Determination of the rate constant of the reaction.

We present Hubble Space Telescope imaging of a pre-explosion counterpart to SN 2019yvr obtained 2.6 yr before its explosion as a type Ib supernova (SN Ib). Aligning to a post-explosion Gemini-S/GSAOI image, we demonstrate that there is a single source consistent with being the SN 2019yvr progenitor system, the second SN Ib progenitor candidate after iPTF13bvn. We also analysed pre-explosion Spitzer /Infrared Array Camera (IRAC) imaging, but we do not detect any counterparts at the SN location. SN 2019yvr was highly reddened, and comparing its spectra and photometry to those of other, less extinguished SNe Ib we derive |$E(B-V)=0.51\substack{+0.27\\ -0.16}$|  mag for SN 2019yvr. Correcting photometry of the pre-explosion source for dust reddening, we determine that this source is consistent with a log (L /L⊙) = 5.3 ± 0.2 and |$T_{\mathrm{eff}} = 6800\substack{+400\\ -200}$|  K star. This relatively cool photospheric temperature implies a radius of 320 |$\substack{+30\\ -50}~\mathrm{ R}_{\odot}$|⁠ , much larger than expectations for SN Ib progenitor stars with trace amounts of hydrogen but in agreement with previously identified SN IIb progenitor systems. The photometry of the system is also consistent with binary star models that undergo common envelope evolution, leading to a primary star hydrogen envelope mass that is mostly depleted but still seemingly in conflict with the SN Ib classification of SN 2019yvr. SN 2019yvr had signatures of strong circumstellar interaction in late-time (>150 d) spectra and imaging, and so we consider eruptive mass-loss and common envelope evolution scenarios that explain the SN Ib spectroscopic class, pre-explosion counterpart, and dense circumstellar material. We also hypothesize that the apparent inflation could be caused by a quasi-photosphere formed in an extended, low-density envelope, or circumstellar matter around the primary star. [ABSTRACT FROM AUTHOR]

The active galaxy NGC 4151 has a crucial role as one of only two active galactic nuclei for which black hole mass measurements based on emission line reverberation mapping can be calibrated against other dynamical techniques. Unfortunately, effective calibration requires accurate knowledge of the distance to NGC 4151, which is not at present available. Recently reported distances range from 4 to 29 megaparsecs. Strong peculiar motions make a redshift-based distance very uncertain, and the geometry of the galaxy and its nucleus prohibit accurate measurements using other techniques. Here we report a dust-parallax distance to NGC 4151 of megaparsecs. The measurement is based on an adaptation of a geometric method that uses the emission line regions of active galaxies. Because these regions are too small to be imaged with present technology, we use instead the ratio of the physical and angular sizes of the more extended hot-dust emission as determined from time delays and infrared interferometry. This distance leads to an approximately 1.4-fold increase in the dynamical black hole mass, implying a corresponding correction to emission line reverberation masses of black holes if they are calibrated against the two objects with additional dynamical masses. [ABSTRACT FROM AUTHOR]

We present an algorithm for inferring the dynamical mass of galaxy clusters directly from their respective phase-space distributions, that is, the observed line-of-sight velocities and projected distances of galaxies from the cluster centre. Our method employs normalizing flows, a deep neural network capable of learning arbitrary high-dimensional probability distributions, and inherently accounts, to an adequate extent, for the presence of interloper galaxies which are not bounded to a given cluster, the primary contaminant of dynamical mass measurements. We validate and showcase the performance of our neural flow approach to robustly infer the dynamical mass of clusters from a realistic mock cluster catalogue. A key aspect of our novel algorithm is that it yields the probability density function of the mass of a particular cluster, thereby providing a principled way of quantifying uncertainties, in contrast to conventional machine learning (ML) approaches. The neural network mass predictions, when applied to a contaminated catalogue with interlopers, have a mean overall logarithmic residual scatter of 0.028 dex, with a lognormal scatter of 0.126 dex, which goes down to 0.089 dex for clusters in the intermediate- to high-mass range. This is an improvement by nearly a factor of 4 relative to the classical cluster mass scaling relation with the velocity dispersion, and outperforms recently proposed ML approaches. We also apply our neural flow mass estimator to a compilation of galaxy observations of some well-studied clusters with robust dynamical mass estimates, further substantiating the efficacy of our algorithm. [ABSTRACT FROM AUTHOR]

Context. Galaxies that hosted many core-collapse supernova (SN) explosions can be used to study the conditions necessary for the formation of massive stars. NGC 2770 was dubbed an SN factory because it hosted four core-collapse SNe in 20 years (three type Ib and one type IIn). Its star formation rate (SFR) was reported to not be enhanced and, therefore, not compatible with such a high SN rate. Aims. We aim to explain the high SN rate of NGC 2770. Methods. We used archival H I line data for NGC 2770 and reinterpreted the Hα and optical continuum data. Results. Even though the continuum-based SFR indicators do not yield high values, the dust-corrected Hα luminosity implies a high SFR, consistent with the high SN rate. Such a disparity between the SFR estimators is an indication of recently enhanced star formation activity because the continuum indicators trace long timescales of the order of 100 Myr, unlike the line indicators, which trace timescales of the order of 10 Myr. Hence, the unique feature of NGC 2770 compared to other galaxies is the fact that it was observed very shortly after the enhancement of the SFR. It also has high dust extinction, E(B − V) above 1 mag. We provide support for the hypothesis that the increased SFR in NGC 2770 is due to the interaction with its companion galaxies. We report an H I bridge between NGC 2770 and its closest companion and the existence of a total of four companions within 100 kpc (one identified for the first time). There are no clear H I concentrations close to the positions of SNe in NGC 2770 such as those detected for hosts of gamma-ray bursts (GRBs) and broad-lined SNe type Ic (IcBL). This suggests that the progenitors of type Ib SNe are not born out of recently accreted atomic gas, as was suggested for GRB and IcBL SN progenitors. [ABSTRACT FROM AUTHOR]

The theoretical framework of cosmology is mainly defined by gravity, of which general relativity is the current model. Recent tests of general relativity within the Lambda Cold Dark Matter (?CDM) model have found a concordance between predictions and the observations of the growth rate and clustering of the cosmic web. General relativity has not hitherto been tested on cosmological scales independently of the assumptions of the ?CDM model. Here we report an observation of the gravitational redshift of light coming from galaxies in clusters at the 99 per cent confidence level, based on archival data. Our measurement agrees with the predictions of general relativity and its modification created to explain cosmic acceleration without the need for dark energy (the f(R) theory), but is inconsistent with alternative models designed to avoid the presence of dark matter. [ABSTRACT FROM AUTHOR]

Reports on an optical spectrum of the afterglow from gamma ray burst (GRB) 990123 which shows an absorption system at a redshift of z = 1.600. Upper limit indications for a hydrogen Lyman alpha forest and an ultraviolet photometry; Implication, from favored cosmological parameters, that an isotropic energy release equivalent to the rest mass of 1.8 neutron stars was emitted in gamma rays; Nonisotropic emission as a possible resolution to the energy problem.

A field campaign in a deciduous forest in Ispra, Italy, was performed by the Joint Research Centre, Ispra, Italy, together with University of Innsbruck, Austria, in 2013, using PTR-ToF-MS (proton transfer reaction - time-of-flight - mass spectrometry), PTR-QMS (proton transfer reaction - quadrupole mass spectrometry), FIS (fast isoprene sensor) and other instrumentations. The main purpose of the campaign was to measure volatile organic carbon (VOC). One of the outcomes of this investigation was the comparison between the three VOC measurement techniques, focusing on the VOC-flux values that could be measured, VOC-volume-mixing-ratio (VOC-VMR) values that could be measured, the number of VOCs identified/measured, and finally if any oxidation products from the primary emitted VOC could be identified/measured. To the best of our knowledge, it is the first time that these three techniques have been used simultaneously during a campaign in a forest, and the comparison of the three techniques is presented in details (PTR-ToF-MS, PTR-QMS and FIS). It was concluded that the isoprene data generated by the three instruments were in good agreement. With PTR-ToF-MS, the following main results were achieved during the summer campaign 2013: The VMR of isoprene was measured up to 16 ppb; large fluxes of isoprene with values up to 53 nmol m−2 s−1 by PTR-ToF-MS; mean diurnal (24 h) averages of VMR of isoprene of (1.07 ± 0.53) ppb and mean diurnal (24 h) flux of isoprene of (5.20 ± 2.42) nmol m−2 s−1. For the isoprene oxidation products methyl-vinyl-ketone/methacrolein (MVK/MACR), VMRs of (0.42 ± 0.22) ppb were measured as a mean diurnal (24 h) average. Mean diurnal (24 h) flux of MVK/MACR were measured to be (0.06 ± 0.04) nmol m−2 s−1; for the monoterpenes, the VMR was measured to be (0.10 ± 0.09) ppb mean diurnal (24 h) and mean diurnal (24 h) flux of monoterpenes to be (0.08 ± 0.05) nmol m−2 s−1. Detailed descriptions of the fluxes/VMRs of other VOCs, acetone/methanol/acetaldehyde, are also presented. The results obtained here have also been compared to several other similar studies and campaigns. [ABSTRACT FROM AUTHOR]

INTRODUCTION: The Hubble constant(H0) quantifies the rate at which the Universe is expanding. Measurements of thermonuclear supernovae (SNe) inthenearby Universehave yielded H0 ¼ 73:0 T 1:0 km s1 Mpc1. It has been predicted that observations of a supernova (SN) that is multiply imaged by a foreground gravitational lens could, in principle, be used to measure H0. [Extracted from the article]

The article focuses on the discovery of four images of a single supernova caused by an early-type cluster galaxy gravitational lens. It states that researchers used the Hubble Space Telescope to discover a supernova forming an Einstein cross configuration and mentions the lens also created multiple images of the spiral galaxy the supernova occurred in. It talks about the use of the multiple images to examine the cosmic expansion rate and the distribution of matter in the galaxy lens.

Observations of the high redshift Universe through narrow-band filters have proven very successful in the last decade. The 4-m VISTA telescope, equipped with the wide-field camera VIRCAM, offers a major step forward in wide-field near-infrared imaging, and in order to utilise VISTA's large field-of-view and sensitivity, the Dark Cosmology Centre provided a set of 16 narrow-band filters for VIRCAM. These NB118 filters are centered at a wavelength near 1.19 μm in a region with few airglow emission lines. The filters allow the detection of Hα emitters at z = 0.8, Hβ and [O III] emitters at z ≈ 1.4, [O II] emitters at z = 2.2, and Lyα emitters at z = 8.8. Based on guaranteed time observations of the COSMOS field we here present a detailed description and characterization of the filters and their performance. In particular we provide sky-brightness levels and depths for each of the 16 detector/filter sets and find that some of the filters show signs of some red-leak. We identify a sample of 2 x 103 candidate emission-line objects in the data. Cross-correlating this sample with a large set of galaxies with known spectroscopic redshifts we determine the "in situ" passbands of the filters and find that they are shifted by about 3.5-4 nm (corresponding to 30% of the filter width) to the red compared to the expectation based on the laboratory measurements. Finally, we present an algorithm to mask out persistence in VIRCAM data. Scientific results extracted from the data will be presented separately. [ABSTRACT FROM AUTHOR]

We discuss the results of the analysis of multi-wavelength data for the afterglows of GRB 081007 and GRB 090424, two bursts detected by Swift. One of them, GRB 081007, also shows a spectroscopically confirmed supernova, SN 2008hw, which resembles SN 1998bw in its absorption features, while the maximum magnitude may be fainter, up to 0.7 mag, than observed in SN 1998bw. Bright optical flashes have been detected in both events, which allows us to derive solid constraints on the circumburst-matter density profile. This is particularly interesting in the case of GRB 081007, whose afterglow is found to be propagating into a constant-density medium, yielding yet another example of a gamma-ray burst (GRB) clearly associated with a massive-star progenitor which did not sculpt the surroundings with its stellar wind. There is no supernova component detected in the afterglow of GRB 090424, likely due to the brightness of the host galaxy, comparable to the Milky Way. We show that the afterglow data are consistent with the presence of both forward- and reverse-shock emission powered by relativistic outflows expanding into the interstellar medium. The absence of optical peaks due to the forward shock strongly suggests that the reverse-shock regions should be mildly magnetized. The initial Lorentz factor of outflow of GRB 081007 is estimated to be Γ ~ 200, while for GRB 090424 a lower limit of Γ > 170 is derived.We also discuss the prompt emission of GRB 081007, which consists of just a single pulse. We argue that neither the external forward-shock model nor the shock-breakout model can account for the prompt emission data and suggest that the single-pulse-like prompt emission may be due to magnetic energy dissipation of a Poynting-flux-dominated outflow or to a dissipative photosphere. [ABSTRACT FROM AUTHOR]

We present the discovery of a Type Ia supernova (SN) at redshift z = 1.914 from the CANDELS multi-cycle treasury program on the Hubble Space Telescope (HST). This SN was discovered in the infrared using the Wide- Field Camera 3, and it is the highest-redshift Type Ia SN yet observed. We classify this object as a SN Ia by comparing its light curve and spectrum with those of a large sample of Type Ia and core-collapse SNe. Its apparent magnitude is consistent with that expected from the ΛCDM concordance cosmology.We discuss the use of spectral evidence for classification of z > 1.5 SNe Ia using HST grism simulations, finding that spectral data alone can frequently rule out SNe II, but distinguishing between SNe Ia and SNe Ib/c can require prohibitively long exposures. In such cases, a quantitative analysis of the light curve may be necessary for classification. Our photometric and spectroscopic classification methods can aid the determination of SN rates and cosmological parameters from the full high-redshift CANDELS SN sample. [ABSTRACT FROM AUTHOR]

Soft X-ray absorption in excess of Galactic is observed in the afterglows of most gamma-ray bursts (GRBs), but the correct solution to its origin has not been arrived at after more than a decade of work, preventing its use as a powerful diagnostic tool. We resolve this long-standing problem and find that absorption by He in the GRB's host H II region is responsible for most of the absorption. We show that the X-ray absorbing column density (NHX ) is correlated with both the neutral gas column density and with the optical afterglow's dust extinction (AV). This correlation explains the connection between dark bursts and bursts with high NHX values. From these correlations, we exclude an origin of the X-ray absorption which is not related to the host galaxy, i.e., the intergalactic medium or intervening absorbers are not responsible. We find that the correlation with the dust column has a strong redshift evolution, whereas the correlation with the neutral gas does not. From this, we conclude that the column density of the X-ray absorption is correlated with the total gas column density in the host galaxy rather than the metal column density, in spite of the fact that X-ray absorption is typically dominated by metals. The strong redshift evolution of NHX/AV is thus a reflection of the cosmic metallicity evolution of star-forming galaxies and we find it to be consistent with measurements of the redshift evolution of metallicities for GRB host galaxies. We conclude that the absorption of X-rays in GRB afterglows is caused by He in the H II region hosting the GRB. While dust is destroyed and metals are stripped of all of their electrons by the GRB to great distances, the abundance of He saturates the He-ionizing UV continuum much closer to the GRB, allowing it to remain in the neutral or singly-ionized state. Helium X-ray absorption explains the correlation with total gas, the lack of strong evolution with redshift, as well as the absence of dust, metal or hydrogen absorption features in the optical-UV spectra. [ABSTRACT FROM AUTHOR]

ABSTRACT Strong gravitational lensing magnifies the flux from distant galaxies, allowing us to detect emission lines that would otherwise fall below the detection threshold for medium-resolution spectroscopy. Here we present the detection of temperature-sensitive oxygen emission lines from three galaxies at 2 ≲ z ≲ 3.5, which enables us to directly determine the oxygen abundances and thereby double the number of galaxies at z > 2 for which this has been possible. The three galaxies have ∼10 per cent solar oxygen abundances in agreement with strong emission-line diagnostics. Carbon and nitrogen ratios relative to oxygen are subsolar as expected for young metal-poor galaxies. Two of the galaxies are Lyman α (Lyα) emitters with rest-frame equivalent widths of 20 and 40 Å, respectively, and their high magnification factors allow us for the first time to gain insight into the physical characteristics of high-redshift Lyα emitters. Using constraints from the physical properties of the galaxies, we accurately reproduce their line profiles with radiative transfer models. The models show a relatively small outflow in agreement with the observed small velocity offsets between nebular emission and interstellar absorption lines. [ABSTRACT FROM AUTHOR]

Abstract: Ships have been found to be major sources of air pollution in harbours. However, from January 1, 2010, a European Union directive requires that all ships at berth or anchorage in European harbours use fuels with a sulphur content of less than 0.1% by weight while previously, outside of Sulphur Emission Control Areas, up to 4.5% were allowed. The impact of this directive on air quality in some Mediterranean harbours was investigated based on observations made from August to October 2009 and 2010 at a monitoring station placed on a cruise ship, Costa Pacifica, following a fixed weekly route in the Western Mediterranean. The concentrations of SO2 were found to decrease significantly from 2009 to 2010 in three out of the four EU harbours; the average decrease of the daily mean concentrations in the different harbours was 66%. The decrease of SO2 was not statistically significant in the harbour of Barcelona because of large day-to-day variations, however measurements from monitoring stations in the harbour zone of Barcelona as well as downwind of the harbour of Palma de Mallorca confirm a strong decrease in the SO2 concentrations from 2009 to 2010. No decrease was observed in the non-EU harbour of Tunis. Neither NO x nor BC concentrations showed significant changes in any of the harbours. [Copyright &y& Elsevier]

We report the discovery of a Type la supernova (SN Ia) at redshift z = 1.55 with the infrared detector of the Wide Field Camera 3 (WFC3-IR) on the Hubble Space Telescope (HST). This object was discovered in CANDELS imaging data of the Hubble Ultra Deep Field and followed as part of the CANDELS+CLASH Supernova project, comprising the SN search components from those two HST multi-cycle treasury programs. This is the highest redshift SN Ia with direct spectroscopic evidence for classification. It is also the first SN Ia at z > 1 found and followed in the infrared, providing a full light curve in rest-frame optical bands. The classification and redshift are securely defined from a combination of multi-band and multi-epoch photometry of the SN, ground-based spectroscopy of the host galaxy, and WFC3-IR grism spectroscopy of both the SN and host. This object is the first of a projected sample at z > 1.5 that will be discovered by the CANDELS and CLASH programs. The full CANDELS+CLASH SN Ia sample will enable unique tests for evolutionary effects that could arise due to differences in SN Ia progenitor systems as a function of redshift. This high-z sample will also allow measurement of the SN Ia rate out to z ≈ 2, providing a complementary constraint on SN Ia progenitor models. [ABSTRACT FROM AUTHOR]

Presents a letter to the editor in response to the result of the First European Young Investigator awards.