We present JWST MIRI and NIRCam imaging of the inner similar to 5 kpc of the M82 superwind at similar to 0.'' 05-0.'' 375 (similar to 0.9-6.5 pc) resolution. Targeted filters probe emission from polycyclic aromatic hydrocarbons (PAHs; F335M, F360M, F770W, F1130W) and continuum (F250M, F360M) The images reveal a network of cool wind filaments traced by PAHs. PAH surface brightness declines with the inverse square of distance to the midplane, suggesting that the incident radiation field from the starburst drives the observed PAH intensity out to +/- 2.5 kpc. The 3.3/11.3 and 3.3/7.7 mu m band ratios show uniformity with distance from the starburst, though comparisons with mid-IR dust emission models indicate a modest shift toward larger PAHs. Outside the disk, 11.3/7.7 mu m increases moderately, reflecting that PAHs become more neutral with distance from the starburst as they are exposed to a declining radiation field and ionization parameter. Overall, PAHs in the wind are consistent with standard-to-large sizes and standard-to-high ionization states. Including Spitzer and Herschel data, PAH abundance (qPAH) is set at similar to 1% in the starburst and remains unchanging out to +/- 5 kpc off the disk. This flat qPAH profile suggests that PAHs are shielded from the hot wind, perhaps residing in the surface layers of cool clouds, with possible replenishment from cloud interiors and enrichment of the halo from previous bursts. In this picture, clouds are not dense enough to promote PAH growth, and they likely undergo radiative cooling and mixing with the hot phase to survive the gauntlet for at least similar to 20 Myr.

Dust extinction curves provide one of the main avenues to understanding the detailed nature of dust grains and accounting for the effects of dust on observations of many astrophysical objects. For the first time, spectroscopic ultraviolet (UV) extinction curves are measured in M33 expanding the sample of Local Group galaxies with such measurements to five. These curves are based on Hubble Space Telescope/Space Telescope Imaging Spectrograph spectra and literature photometry from the UV to the near-infrared. The four measured curves show large variations in their UV shapes including their 2175 & Aring; bump and UV slope strengths. The average extinction of these four sightlines is lower than the averages for other Local Group Galaxies and does not follow the Milky Way (MW) R(V)-dependent relationship. The variations between UV extinction shape parameters and gas-to-dust ratios for the M33 sightlines fall within the variations seen in the combined sample of UV extinction curves in the MW, Large and Small Magellanic Clouds, and M31. The correlation with gas-to-dust ratio is much stronger than the correlation with global metallicity. This strengthens the picture that local conditions like radiation field density and shocks dominate over global galaxy properties like metallicity in determining the wavelength dependence of dust extinction.

We measure the star formation histories (SFHs) from the Scylla survey in ∼98,000 pc ^2 and ∼75,000 pc ^2 of the Small Magellanic Cloud (SMC) and Large Magellanic Cloud (LMC), respectively, using deep Hubble Space Telescope imaging (80% complete to > 1 mag below the ancient main-sequence turnoff, ∼25.1 and 26.0 mag in F475W and F814W) from 74 pointings. We group the fields into eight subregions in the SMC and seven in the LMC. We use the birth rate parameter to identify bursts of star formation and measure their properties in each subregion. Our methodology provides a standardized framework for burst identification and reveals both broad and fine burst characteristics. We identify global and local bursts, defined as those occurring in ≥half or

We present a novel methodology for mapping dust extinction in nearby galaxies at parsec-scale resolution. We apply it to 68 Hubble Space Telescope (HST) fields within the Small and Large Magellanic Clouds (23 fields in the SMC and 45 fields in the LMC) using multiband HST photometry from the Scylla and Metal Evolution Transport and Abundance in the LMC surveys. Our technique leverages kriging, a geostatistical interpolation method built on the principles of Gaussian process regression, combined with Gaussian mixture modeling to statistically isolate background stellar sources and account for line-of-sight depth effects. Three-dimensional dust simulations demonstrate the method's capability to recover column densities to an accuracy of AV approximate to 0.1 mag in fields with at least 1000 sources. The resulting 4 '' resolution (similar to 1 pc) dust maps reveal detailed structure and strong spatial correlation with ancillary interstellar medium (ISM) tracers, especially in star-forming regions like 30 Doradus. Global extinction of total column densities follows log-normal profiles in both galaxies, with the SMC exhibiting slightly higher mean extinction (e mu = 0.47 mag) than the broader LMC (e mu = 0.43 mag), likely due to significant line-of-sight depths. We find systematic offsets between dust mass surface densities (Sigma D) derived from extinction versus far-IR emission in both galaxies, with Sigma D,FIR/Sigma D,AV ratios ranging from 0.6-1.8. This work provides the highest-resolution dust extinction maps in SMC and LMC to date, which offer a vital independent benchmark for constraining dust emissivity, CO-dark gas fractions, and the multiscale structure of the ISM in low-metallicity environments.

We present a catalog of individual stellar and dust extinction properties along close to 500,000 sight lines in the southwest bar of the Small Magellanic Cloud (SMC). The catalog is based on multiband Hubble Space Telescope photometric data spanning near-ultraviolet to near-infrared wavelengths from the Small Magellanic Cloud Investigation of Dust and Gas Evolution survey (SMIDGE) covering a 100 x 200 pc area. We use the probabilistic technique of the Bayesian Extinction And Stellar Tool (BEAST) to model the spectral energy distributions of individual stars in SMIDGE and include the effects of observational uncertainties in the data. We compare BEAST-derived dust extinction properties with tracers of the interstellar medium, such as the emission from the 12CO (2-1) transition (I(CO)), the dust mass surface density (Sigma dust) from far-IR emission, the H i column density (N(H i)) from the 21 cm transition, and the mass fraction of polycyclic aromatic hydrocarbons (PAHs; q PAH, derived from IR emission). We find that the dust extinction (A(V)) in the SMIDGE field is strongly correlated with Sigma dust and I(CO), and less so with N(H i) and q PAH, and suggest potential explanations. Our extinction measurements are also sensitive to the presence of the 2175 & Aring; bump in the extinction curve toward UV bright stars. While most do not show evidence for the bump, we identify similar to 200 lines of sight that are 2175 & Aring; bump candidates. Furthermore, we find distinct structures in the dust extinction-distance distributions that provide insights into the 3D geometry of the SMC.

By analyzing the spectral energy distributions (SEDs) of resolved stars in nearby galaxies, we can constrain their stellar properties and line-of-sight dust extinction. From the Scylla survey, we obtain ultraviolet to near-infrared photometry from Wide Field Camera 3 on board the Hubble Space Telescope for more than 1.5 million stars in the SMC and LMC. We use the Bayesian Extinction and Stellar Tool (BEAST) to analyze the multiband SEDs of these sources and characterize their initial masses, ages, metallicities, distances, and line-of-sight extinction properties (e.g., A _V , R _V ). We apply quality cuts and perform validation simulations to construct a catalog of over 550,000 stars with high-reliability SED fits, which we use to analyze the stellar content and extinction properties of the SMC and LMC. We detect stars with masses as low as 0.6 M _⊙ . BEAST stellar age distributions show a jump in observed stars around 6 Gyr ago, which agrees with star formation histories. Extinctions ( A _V ) in both galaxies follow a log-normal distribution. We compare A _V with ancillary gas and dust tracers like H i , H α , and far-infrared (FIR) dust emission and find positive correlations on a field-by-field basis. We convert observed A _V to predicted dust surface densities using the Draine et al. model and find A _V -based dust surface densities are a factor of ∼2.5 lower than observed FIR-based dust surface densities, a correction factor similar to other studies.

Photodissociation regions (PDRs) are key to understanding the feedback processes that shape interstellar matter in galaxies. One important type of PDR is the interface between H ii regions and molecular clouds, where far-ultraviolet radiation from massive stars heats gas and dissociates molecules. Photochemical models predict that as metallicity decreases, the C/CO transition occurs at greater depths in the PDR compared to the H/H2 transition, increasing the extent of CO-dark H2 gas in low-metallicity environments. This prediction has been difficult to test outside the Milky Way due to the lack of high-spatial-resolution observations tracing H2 and CO. This study examines a low-metallicity PDR in the N13 region of the Small Magellanic Cloud (SMC), where we spatially resolve the ionization front, the H2 dissociation front, and the C/CO transition using 12CO J = 2-1, 3-2, and [C I] 1-0 observations from the Atacama Large Millimeter/submillimeter Array and near-infrared spectroscopy of the H2 2.12 1-0 S(1) vibrational line, and H recombination lines from the James Webb Space Telescope. Our analysis shows that the separation between the H/H2 and C/CO boundaries is approximately 0.043 +/- 0.013(stat.) +/- 0.0036(syst.) pc (equivalent to 0.'' 146 +/- 0.'' 042(stat.)+/- 0.'' 012(syst.) at the SMC's distance of 62 kpc), defining the spatial extent of the CO-dark H2 region. Compared to our plane-parallel PDR models, we find that a constant-pressure model matches the observed structure better than a constant-density one. Overall, we find that the PDR model does well at predicting the extent of the CO-dark H2 layer in N13. This study represents the first resolved benchmark for low-metallicity PDRs.

The absolute flux calibration of the Mid-Infrared Instrument imaging and coronagraphy is based on observations of multiple stars taken during the first 2.5 yr of James Webb Space Telescope operations. The observations were designed to ensure that the flux calibration is valid for a range of flux densities, different subarrays, and different types of stars. The flux calibration was measured by combining observed aperture photometry corrected to infinite aperture with predictions based on previous observations and models of stellar atmospheres. A subset of these observations was combined with model point-spread functions to measure the corrections to infinite aperture. Variations in the calibration factor with time, flux density, background level, type of star, subarray, integration time, rate, and well depth were investigated, and the only significant variations were with time and subarray. Observations of the same star taken approximately every month revealed a modest time-dependent response loss seen mainly at the longest wavelengths. This loss is well characterized by a decaying exponential with a time constant of similar to 200 days. After correcting for the response loss, the band-dependent scatter around the corrected average (i.e., repeatability) was found to range from 0.1% to 1.2%. Signals in observations taken with different subarrays can be lower by up to 3.4% compared to FULL frame. After correcting for the time and subarray dependencies, the scatter in the calibration factors measured for individual stars ranges from 1% to 4% depending on the band. The formal uncertainties on the flux calibration averaged for all observations are 0.3%-1.0%, with longer-wavelength bands generally having larger uncertainties.

The Panchromatic Hubble Andromeda Southern Treasury (PHAST) is a large 195-orbit Hubble Space Telescope program imaging ∼0.45 deg 2 of the southern half of M31's star-forming disk at optical and near-ultraviolet (NUV) wavelengths. The PHAST survey area extends the northern coverage of the Panchromatic Hubble Andromeda Treasury (PHAT) down to the southern half of M31, covering out to a radius of ∼13 kpc along the southern major axis and in total ∼two-thirds of M31's star-forming disk. This new legacy imaging yields stellar photometry of over 90 million resolved stars using the Advanced Camera for Surveys in the optical (F475W and F814W), and the Wide Field Camera 3 (WFC3) in the NUV (F275W and F336W). The photometry is derived using all overlapping exposures across all bands, and achieves a 50% completeness-limited depth of F475W ∼ 27.7 in the lowest surface density regions of the outer disk and F475W ∼ 26.0 in the most crowded, high surface brightness regions near M31's bulge. We provide extensive analysis of the data quality, including artificial star tests to quantify completeness, photometric uncertainties, and flux biases, all of which vary due to the background source density and the number of overlapping exposures. We also present seamless population maps of the entire M31 disk, which show relatively well-mixed distributions for stellar populations older than 1–2 Gyr, and highly structured distributions for younger populations. The combined PHAST + PHAT photometry catalog of ∼0.2 billion stars is the largest ever produced for equidistant sources and is available for public download by the community.

Using the Hubble Space Telescope/Space Telescope Imaging Spectrograph, ultraviolet (UV) extinction curves have been measured in M31 along 13 new sight lines, increasing the M31 sample to 17. This sample covers a wide area of M31, having galactocentric distances of 5–16 kpc, enabling the analysis of UV extinction curve variations over a large region of an external galaxy similar to the Milky Way with global galactic characteristics such as metallicity for the first time. No correlation is found between the extinction parameters and galactocentric distance, which might be expected if there is a radial metallicity gradient in M31. Most of the new UV extinction curves presented here are significantly different from the average extinction curves of the Milky Way, Large Magellanic Cloud (LMC), and Small Magellanic Cloud (SMC), but the average M31 extinction curve is similar to the average extinction curve in the 30 Dor region of the LMC. The wide range of extinction curves seen in each individual Local Group galaxy suggests that global galactic properties such as metallicity may be less important than the local environmental conditions, such as density, UV radiation field, and shocks along each sight line. The combined behavior of the Milky Way, LMC, SMC, and now M31 UV extinction curves supports the idea that there is a family of curves in the Local Group with overlapping dust grain properties between different galaxies.

The dusty interstellar medium (ISM) of the Milky Way is distributed in a complex, cloudy structure. It is fundamental to the radiation balance within the Milky Way, provides a reaction surface to form complex molecules, and is the feedstock for future generations of stars and planets. The life cycle of interstellar dust is not completely understood, and neither are its structure nor composition. The abundance, composition, and structure of dust in the diffuse ISM can be determined by combining infrared, optical, and ultraviolet spectroscopy. JWST enables measurement of the faint absorption of ISM dust grains against bright stars at kiloparsec distances across the infrared spectrum. Here we present an overview of the project “Webb Investigation of Silicates, Carbons, and Ices” (WISCI) along with interpretation of two targets, GSC 08152-02121 and CPD-59 5831. Observations of 12 WISCI target stars were taken by JWST, the Hubble Space Telescope, Himalayan Chandra Telescope, and the Very Large Telescope. We use these to characterize the targets’ spectral types and calculate their line-of-sight extinction parameters, A V and R V . We find absorption in the JWST spectra of GSC 08152-02121 and CPD-59 5831 associated with carbonaceous dust around 3.4 and 6.2 μ m and amorphous silicates at 9.7 μ m. In GSC 08152-02121, we also find indications of absorption by trapped water around 3 μ m. This first look from WISCI demonstrates the line-of-sight variability within the sample, and the program’s potential to identify and correlate features across ultraviolet to mid-infrared wavelengths.

BACKGROUND:Bacillus thuringiensis (Bt) insecticidal proteins, including crystalline (Cry) proteins and vegetative insecticidal proteins (Vips), are extensively used in transgenic crops due to their efficacy, low environmental impact, and safety. The fall armyworm, Spodoptera frugiperda, has evolved practical resistance to Cry1Fa, yet no practical resistance to Vip3Aa has been documented. However, both laboratory selection and field screen studies indicate a high potential for this pest to evolve resistance to Vip3Aa, making it crucial to evaluate potential resistance genes. HaVipR1 has recently been identified as a key determinant of Vip3Aa resistance in the cotton bollworm, Helicoverpa armigera. This study investigated whether the HaVipR1-homologous gene in S. frugiperda (SfVipR1) is similarly involved in Vip3Aa resistance. RESULTS:We employed CRISPR/Cas9 technology to generate a homozygous knockout strain of SfVipR1. In comparison with the parent susceptible YJ-19 strain, the knockout strain (Sfru-KO) exhibited high-level resistance to Vip3Aa (>1850-fold) but showed no cross resistance to Cry1Fa. Resistance to Vip3Aa in Sfru-KO is autosomal, recessive, and genetically linked with SfVipR1. CONCLUSION:Disruption of SfVipR1 results in high-level resistance to Vip3Aa, highlighting SfVipR1 has a critical role in Vip3Aa toxicity in S. frugiperda, despite the exact mechanism remaining unclear. Early detection of SfVipR1 mutant alleles in the field is essential for developing adaptive resistance management strategies against S. frugiperda. © 2025 Society of Chemical Industry.

Context. The Medium Resolution Spectrometer (MRS) of the Mid-InfraRed Instrument (MIRI) on the James Webb Space Telescope (JWST) is affected by interferometric spectral fringing, due to scattering within the detector and dichroic layers. The amplitude of these oscillations on the spectrum can be up to 30%. Correcting them is non-trivial, since the depth and phase of the fringes depend strongly on the illumination pattern and the way the pixels sample it. By default the JWST pipeline uses static fringe flats to divide out the fringes. These flats are representative for a spatially homogeneous extended source, but not for point sources. The significant residuals in the data are removed by using a self-calibrating correction step which can alter physical features in the spectra in a non-systematic way. Aims. We build on our corrections from Paper I (Gasman et al., 2024, A&A, 688, A226) in this series, to derive a library of detector-based fringe flats for unresolved sources in a nine-point mosaic around all nominal MRS point source dither positions. We provide users with either an absolute or interpolated fringe flat that can correct the fringes without the need for self-calibration, hence mitigating the risk of altering astrophysical features of interest. Methods. We used the data of 10 Lac from the Cycle 2 calibration programme 3779 to create the library of fringe flats. By removing the continuum and spectral features from the data at the detector-plane level, each of the nine mosaic points around the eight dither positions resulted in a pointing specific fringe flat. By assessing the difference in response between the individual pointings, we found correction factors to bring all the spectra to the same level, and used these to derive a single spectrophotometric calibration curve per band. Results. The library of fringe flats is able to reduce the remaining power of the fringe frequencies on the detector by up to two orders of magnitude compared to the current pipeline flats tailored to extended sources. This improvement carries over to the residuals in the cube spaxels, where the contrast is reduced from >10% to <1-2%. This becomes less apparent after extracting a spectrum from the cube, where in channel 1 averaging of fringe phases in the current pipeline case can reduce its residual contrast. The spectrophotometric calibration curves have a root-mean squared variation of less than a percent in all bands except bands 4B and 4C, while channels 2 and 3 have a stability within 0.5%. Sources taken without target acquisition (TA) fall outside the mosaic grid, but our correction improves the defringing depending on the source location. Conclusions. The improvements in fringe residual found are significant on the detector and spectrum-level. The corrections derived here are directly compatible with the current JWST pipeline infrastructure, and work best for unresolved sources observed with TA in one of the nominal point-source dither patterns.

We introduce a new photometric mapping method for the James Webb Space Telescope (JWST) to measure the spatial distribution of carbonaceous dust, siliceous dust, and water ice by using absorption features arising from the grains in the dense interstellar medium (ISM). Employing NIRCam and MIRI imaging filters, low-resolution spectroscopic data can be obtained to measure the optical depths of the 3.0 μ m water ice –OH feature, the 3.4 μ m aliphatic hydrocarbon –CH feature, and the 10 μ m silicate –SiO feature for large fields of view. This method provides extensive statistical data of the grains across wide fields in the ISM at minimal observing cost. In this study, we present its application on observational data from the literature to validate the measured optical depths and simulations to assess the accuracy of the method under various conditions. We showed that the photometric method can be employed to obtain reasonably accurate measurements of optical depth. We demonstrate that JWST optical depth maps enable the independent exploration of abundance distributions of major grain components across a wide spatial coverage in the ISM.

Context. The UVJ color-color diagram is a widely used diagnostic to separate star-forming and quiescent galaxies. Observational data from photometric surveys reveal a strong stellar mass trend, with higher-mass star-forming galaxies being systematically more dust-reddened. Aims. We analyze the UVJ diagram in the TNG100 cosmological simulation at cosmic noon (z approximate to 2). Specifically, we focus on the trend between UVJ colors and mass, which has not been reproduced in any cosmological simulation thus far. Methods. We applied the SKIRT dust radiative transfer code to the TNG100 simulation to generate rest-frame UVJ fluxes. These UVJ colors were then compared to observational data from several well-studied extragalactic fields from the CANDELS/3D-HST programs, augmented by recent JWST/NIRCam photometry. Results. Quiescent and low-mass (M-star less than or similar to 10(10.5) M-circle dot) galaxies at cosmic noon do not require significant levels of dust reddening, as opposed to massive (M-star greater than or similar to 10(11) M-circle dot) star-forming galaxies. An extensive range of possible dust models fall short of the required dust reddening in V - J color for massive star-forming galaxies, with the simulated galaxies being too blue by approximate to 0.9 mag. Conclusions. We find that only variations in the star-to-dust geometries of the simulated galaxies are able to yield V - J colors that are red enough to match the observations. A toy model with isolated dust screens around younger stellar populations (with ages below similar to 1 Gyr) can reproduce the observational data, while all "conventional" dust radiative transfer models (where the dust distribution follows the metals in the interstellar medium) fail to achieve the required V - J colors.

We describe the spectrophotometric calibration of the Mid-Infrared Instrument’s (MIRI) Medium Resolution Spectrometer (MRS) aboard the James Webb Space Telescope. This calibration is complicated by a time-dependent evolution in the effective throughput of the MRS; this evolution is strongest at long wavelengths, approximately a factor of 2 at 25 μ m over the first 2 yr of the mission. We model and correct for this evolution through regular observations of internal calibration lamps. Pixel flat fields are constructed from observations of the infrared-bright planetary nebula NGC 7027, and photometric aperture corrections from a combination of theoretical models and observations of bright standard stars. We tie the 5–18 μ m flux calibration to high signal-to-noise ratio (S/N; ∼600–1000) observations of the O9 V star 10 Lacertae, scaled to the average calibration factor of nine other spectrophotometric standards. We calibrate the 18–28 μ m spectral range using a combination of observations of main belt asteroid 515 Athalia and the circumstellar disk around young stellar object SAO 206462. The photometric repeatability is stable to better than 1% in the wavelength range 5–18 μ m, and the S/N ratio of the delivered spectra is consistent between bootstrapped measurements, pipeline estimates, and theoretical predictions. The MRS point-source calibration agrees with that of the MIRI imager to within 1% from 7 to 21 μ m and is approximately 1% fainter than prior Spitzer observations, while the extended source calibration agrees well with prior Cassini Composite Infrared Spectrometer and Voyager Infrared Interferometer Spectrometer and Radiometer observations.

We present resolved 3.6-250 mu m dust spectral energy distribution (SED) fitting for similar to 800 nearby galaxies. We measure the distribution of radiation field intensities heating the dust, the dust mass surface density (Sigma(d)), and the fraction of dust in the form of polycyclic aromatic hydrocarbons (PAHs; q PAH). We find that the average interstellar radiation field (U) is correlated both with stellar mass surface density (Sigma(star)) and star formation rate surface density (Sigma SFR), while more intense radiation fields are only correlated with Sigma SFR. We show that q PAH is a steeply decreasing function of Sigma SFR, likely reflecting PAH destruction in H ii regions. Galaxy-integrated q PAH is strongly, negatively correlated with specific star formation rate (sSFR) and offset from the star-forming "main sequence" (Delta MS), suggesting that both metallicity and star formation intensity play a role in setting the global q PAH. We also find a nearly constant M-d/M-* ratio for galaxies on the main sequence, with a lower ratio for more quiescent galaxies, likely due to their lower gas fractions. From these results, we construct prescriptions to estimate the radiation field distribution in both integrated and resolved galaxies. We test these prescriptions by comparing our predicted U to results of SED fitting for stacked "main-sequence" galaxies at 0 < z < 4 from M. B & eacute;thermin et al. and find sSFR is an accurate predictor of U even at these high redshifts. Finally, we describe the public delivery of matched-resolution Wide-field Infrared Survey Explorer and Herschel maps along with the resolved dust SED-fitting results through the Infrared Science Archive.

The mid-infrared spectrum of star-forming, high metallicity galaxies is dominated by emission features from aromatic and aliphatic bonds in small carbonaceous dust grains, often referred to as polycyclic aromatic hydrocarbons (PAHs). In metal-poor galaxies, the abundance of PAHs relative to the total dust sharply declines, but the origin of this deficit is unknown. We present JWST observations that detect and resolve emission from PAHs in the 7

We present the initial results of the Measuring Extinction and Abundances of Dust project, with a focus on the dust extinction features observed in our JWST near- and mid-infrared spectra of nine diffuse Milky Way sightlines (1.2 ≤ A ( V ) ≤ 2.5). For the first time, we find strong correlations between the 10 μ m silicate feature strength and the column densities of Mg, Fe, and O in dust. This is consistent with the well-established theory that Mg- and Fe-rich silicates are responsible for this feature. We obtain an average stoichiometry of the silicate grains in our sample of Mg:Fe:O = 1.1:1:11.2, constraining the grain composition. We find variations in the feature properties, indicating that different sightlines contain different types of silicates. In the average spectrum of our sample, we tentatively detect features around 3.4 and 6.2 μ m, which are likely caused by aliphatic and aromatic/olefinic hydrocarbons, respectively. If real, to the best of our knowledge, this is the first detection of hydrocarbons in purely diffuse sightlines with A ( V ) ≤ 2.5, confirming the presence of these grains in diffuse environments. We detected a 3 μ m feature toward HD073882 and tentatively in the sample average, likely caused by water ice (or solid-state water trapped on silicate grains). If confirmed, to the best of our knowledge, this is the first detection of ice in purely diffuse sightlines with A ( V ) ≤ 2.5, supporting previous findings that these molecules can exist in the diffuse interstellar medium.