Strong gravitational lensing by massive galaxy clusters offers rare opportunities to observe multiple images of distant (z from its host center. This work shows that extended image modeling in lensing clusters simultaneously reduces the uncertainty on lens model parameters and enables spatially resolved analyses of lensed transients' host galaxies. Such modeling advances are expected to play an important role in future cosmological analyses using strongly lensed SNe. Type Ia supernovae (SNe) and to resolve the properties of their host galaxies. A recent outstanding example is the Type Ia SN H0pe (z=1.78), which the James Webb Space Telescope (JWST) discovered in NIRCam images, when the galaxy cluster PLCK,G165.7+67.0 ( ) at around ∼ 1 z=0.35) still produced three images of it. In this work, we build a new strong lensing model of first using only the positions of multiple images of background galaxies. We then significantly increase the number of constraints around the position of SN H0pe by modeling the extended surface brightness of the SN host galaxy. Including extended image information reduces the average uncertainty on mass model parameters by more than an order of magnitude. We also study the spatial distribution of dust in the arc to estimate the dust extinction at the position of SN H0pe. We find good statistical agreement of the extinction estimate, at łesssim1σ, with three fully independent methods based on spectral energy distribution fitting. Moreover, our extended-image lens model of allows us to map the dust distribution of the host galaxy from the image plane to the source plane. Supernova H0pe exploded in a region with a relatively high extinction (A_V ≈ 0.9 ̊m mag ̊m kpc

ABSTRACT The Pillars of Creation in M16 represent an iconic star-forming region where stellar feedback shapes molecular cloud evolution. We present a detailed investigation of dust extinction and density structure in the Pillars of Creation using multiband photometric observations from JWST (James Webb Space Telescope) Near-Infrared Camera (NIRCam). A high-resolution (2 arcsec) extinction map reaching depths of $A_V\sim 100$ mag has been constructed using NIRCam filters F090W, F200W, F335M, and F444W. This map clearly reveals the intricate structure of dense gas within the molecular cloud in the Pillars of Creation region. Analysis of the column density probability distribution function exhibits a characteristic lognormal distribution at intermediate extinctions ($A_V\approx 10\!-\!30$ mag), which transitions to a power-law tail at high extinctions ($A_V \gtrsim 30$ mag) where star-forming cores reside. The power-law slope $\alpha$ displays significant spatial variation, steepening from $\alpha \approx 2.0$ at the pillar tips facing the NGC 6611 cluster to $\alpha \approx 4.0$ in regions distant from the cluster. This systematic gradient demonstrates that stellar feedback not only disperses molecular clouds but can also locally enhance the formation of dense, self-gravitating structures through radiative compression.

Recent spectroscopic surveys provide element abundances for large samples of Milky Way stars, from which stellar parameters can be inferred. Stellar ages, among them, are both a notoriously difficult parameter to estimate and a fundamental property for Galactic archaeology studies. We aim to develop a model-driven deep learning approach to age determination by training neural networks on stellar evolutionary grids. Contrary to the usual data-driven deep learning approach of using prior age estimates as training data, our method has the potential for a wider and less biased range of application. The low computational cost of deep learning methods compared to, for example, Bayesian isochrone fitting enables a broad analysis of large spectroscopic catalogues. We trained multilayer perceptrons on different stellar evolutionary grids to map M/H , M_G, $(G_ BP -G_ RP )$ to stellar age τ. We combined Gaia photometry and parallaxes, metallicities, and α elements from spectroscopic surveys and extinction maps, which are passed through neural networks to estimate stellar ages. We applied our method to the LAMOST DR10, GALAH DR3 & DR4, and APOGEE DR17 spectroscopic surveys, estimating ages using the BaSTI tracks and other stellar evolutionary models. We leveraged this novel technique to study, for the first time, differences in age estimates from several evolutionary grids applied to very large datasets. In addition, we dated 13 open clusters and one globular cluster, finding a median absolute deviation with literature ages of 0.20 Gyr. Along with the stellar age catalogues from our estimates, we release (Neural Estimator of Stellar Times), a python package to estimate stellar age based on this work, as well as a web interface. NEST We show that, when using the same evolutionary grid, our method retrieves the same ages as a Bayesian approach similar to SPInS, for only a fraction of the computational cost, with a 60,000 speed-up factor for a typical star. This model-driven deep learning technique thus opens up the way for broad galactic archaeology studies on the largest datasets available today and in the near future with upcoming surveys such as 4MOST.

We show that the ionization of dense molecular clouds can be used to set strong constraints on dark matter models producing UV/X-ray photons in their annihilation or decay. We place robust and competitive constraints on various dark matter models, such as axion-like particles, scalars and sterile neutrinos, for masses between $\sim30$~eV and $10$~keV, and project forecasts to illustrate the potential of this target. We discuss how these constraints can be significantly improved by considering a more refined sample of molecular clouds near the Galactic Center and above the Galactic plane, a detailed modeling of the cosmic-ray ionization contribution and, potentially, a more refined analysis of the gas density in clouds through dust extinction maps. Thus, ionization of molecular clouds emerges as one of the most powerful tools for probing sub-keV dark matter.

We report on the study of the Antlia supernova remnant (SNR), which is an old, nearby remnant of most likely a core-collapse supernova and which has an extent of ∼ 24^ ̧irc in the sky. Since being detected in the ROSAT all-sky survey, it has not been observed in its entirety until the eROSITA all-sky survey (eRASS). The new images of the extended ROentgen Survey with an Imaging Telescope Array (eROSITA) on board Spectrum-RG (SRG) in X-rays covering the entire SNR and its surroundings, the newest radio polarimetry data of the Southern Twenty-Centimeter All-Sky Polarization Survey (STAPS), and additional multi-wavelength data reveal the extent of the SNR and its interaction with the environment. We can thus constrain the distance and understand the evolution of the SNR. We created mosaic images of eRASS data and extracted X-ray spectra in the entire SNR divided into smaller regions. The spectra were compared to thermal plasma models to derive the SNR's physical properties. From the radio polarimetry data, Faraday moment maps were created and compared to optical and X-ray emission. The X-ray emission fills the interior of the shell of the Antlia SNR, which is seen in Hα and also well traced in the Faraday maps. In addition, structures are found in the extinction and Faraday maps, which are (anti-)correlated with the X-ray emission, and suggest the existence of matter in the foreground. We thus constrain the distance to 250 -- 450 pc, yielding a lower limit that is higher than the one suggested before. The morphology in radio, optical, and X-rays suggests that the SNR is expanding in a medium with a general density gradient, as it is located above the Galactic plane. In addition, there seems to be a denser cloud at higher latitudes, with which the outer shock wave is interacting and which causes an indentation in the outer shell. The X-ray spectra suggest that the plasma in the SNR is not in collisional ionisation equilibrium, but seems to be close to equilibrium at lower Galactic latitudes. A little enhancement in Ne or S abundance is found in some regions, though the significance is low. The Faraday moment maps from the polarisation data indicate enhanced magnetic fields along the shell, with small-scale structures that coincide with small filaments in Hα. By combining large-survey data of eRASS and STAPS, we have obtained a better understanding of the morphology, physical properties, and interior features of one of the closest SNRs.

Among galactic novae, many remain poorly characterized due to heterogeneous data, observational challenges, or heavy reddening along the Galactic plane. A detailed characterization is particularly crucial for novae exhibiting peculiar features, such as those belonging to the hybrid class. We present the spectroscopic and photometric evolution of the heavily reddened Nova Vul 2024 (=V615 Vul) from discovery on 29 July 2024 to well into its nebular phase. We obtained daily optical, absolute-fluxed spectroscopy in both low- and high-resolution echelle modes, providing a detailed account of the spectral evolution. Photometric data were primarily sourced from AAVSO, while refined astrometry was performed to assess the positional coincidence with a potential progenitor. Robust determinations of t_3 and E_B-V were achieved, allowing for the application of the Maximum Magnitude–Rate of Decline (MMRD) relation; the resulting distance is in excellent agreement with 3D Galactic extinction maps. Nova Vul 2024 is a very fast nova (t_3=10.7±0.5 d) located at a distance of 5.0±1.0 kpc, suffering from a large reddening (E_B-V =1.6±0.1). Around maximum light, it exhibited a Fe II-type -1 ) and high-velocity P-Cygni absorptions. Following t_3, coinciding with the emergence of hard X-ray emission, the nova displayed pronounced photometric oscillations primarily driven by continuum variations. Simultaneously, He/N features developed alongside Fe II lines, classifying V615 Vul as a rare hybrid nova. During the nebular phase, the ionization level increased, reaching Fe VII and likely Fe X . The ejecta showed no neon overabundance and expanded ballistically, as indicated by the constant widths, profiles, and castellation of the high-resolution emission lines.

Abstract Chemistry in diffuse molecular clouds relies primarily on rapid ion-molecule reactions. Formation of the initial ions, H + and H 2 + , is dominated by cosmic-ray ionization of H and H 2 , making the cosmic-ray ionization rate (denoted ζ (X) for species X) an important parameter for chemical modeling. We have made observations targeting absorption lines of H 3 + , one of the most reliable tracers of ζ (H 2 ), toward diffuse molecular cloud sight lines where the H 2 column density has been directly measured in the ultraviolet, detecting H 3 + in 12 out of 27 sight lines. The 3D-PDR modeling method introduced by M. Obolentseva et al. was used to infer cosmic-ray ionization rates in the clouds along these sight lines, and our combined sample has a mean ionization rate of 5.3 × 10 −17 s −1 with standard deviation 2.5 × 10 −17 s −1 . By associating H 3 + absorption with gas density peaks derived from the differential extinction maps of G. Edenhofer et al., we have constructed a sparsely sampled 3D map of the cosmic-ray ionization rate in targeted regions within about 1 kpc of the Sun. Specific regions show reasonably uniform ionization rates over length scales of tens of parsecs, with the average ionization rate in each region being different. Large differences (factor of 5) in ζ (H 2 ) are found over length scales of about 100 pc. This supports a picture where the cosmic-ray ionization rate varies smoothly over small size scales, but is not uniform everywhere in the Galactic disk, likely being controlled by proximity to particle acceleration sites.

Abstract Dust in elliptical galaxy cores provides insights into the interstellar medium and galactic evolution. I present an automated pipeline analyzing archived Hubble Space Telescope WFPC2 and ACS images to detect and measure dust masses in early-type galaxies. Using iterative unsharp masking with Gaussian smoothing to reconstruct dust-free galaxy models, I derive dust surface densities and estimate total masses from extinction maps using a thin-screen approximation and dust mass absorption coefficient κ λ = 0.77. This automated method enables consistent application to large samples, providing a framework for future large-scale studies.

Abstract Magnetic fields play an important role in star formation but are often difficult to observationally probe in small star-forming molecular clouds. We study two such clouds, L1604 (toward the Galactic anticentre) and L121 (toward the Galactic centre), using R-band polarimetry to investigate their envelope magnetic field ($\theta _{\textrm{B}}^{\mathrm{env}}$) morphology, physical structure, and internal energetics. We find a key distinction: $\theta _{\textrm{B}}^{\mathrm{env}}$ in L1604 is effectively parallel to the Galactic plane, while it is offset by ∼70○ ± 1○ in L121. Additionally, $\theta _{\textrm{B}}^{\mathrm{env}}$ is misaligned with the core minor axes (derived from submillimeter data) by ∼47○ ± 1○ for L1604 and ∼74○ ± 1○ for L121. However, for L121, a much smaller offset of ∼17○ ± 1○ is found when compared with its minor axis obtained from optical data in the literature, suggesting scale-dependent variations in magnetic field geometry. The distances are calculated with using the NIR photometry technique (which uses 2MASS and Gaia DR3) are found to be 816 ± 11 pc for L1604 and 124 ± 1 pc for L121. We use the PNICER technique to create extinction maps and derived physical parameters using Herschel SPIRE data. The mean column densities are ∼(2.2 ± 1.1) × 1021 cm−2 for L1604 and ∼(1.3 ± 0.6) × 1021 cm−2 for L121. The plane-of-sky magnetic field strengths (Bpos), estimate using the Davis–Chandrasekhar–Fermi method, are ∼(47 ± 17) μG for L1604 and ∼(72 ± 23) μG for L121. Both clouds exhibit sub-critical mass-to-flux ratios and sub-Alfvénic conditions, indicating magnetic dominance over gravity and turbulence. Our results highlight that envelopes are magnetically supported, while cores may become supercritical, demanding high-resolution data to trace the envelope-to-core magnetic influence.

Abstract I present a new view of the circumnuclear disk (CND) of NGC 1068 based on stellar–continuum extinction measured on a JWST/NIRCam image at 1.5 μ m. After estimating the underlying stellar background, I derive a two-dimensional extinction map around the nucleus tracing the cold dust distribution. Comparing it with a CO(2–1) emission map obtained with Atacama Large Millimeter/submillimeter Array reveals a remarkable correspondence with the molecular gas distribution, from the global ∼400 pc ring and its ∼130 pc cavity down to the smallest resolved structures. I nevertheless identify large scale relative differences in amplitude, that may indicate that the CND is inclined with respect to the stellar disk. These results demonstrate the potential of JWST to trace molecular structures around active galactic nucleus in the absence of millimetric observations.

Abstract We present a combined photometric and R -band polarimetric study of the Lynds dark clouds L1578 and L1607 to investigate their physical properties—such as distance, column density, and dust temperature—and to examine the morphology of their magnetic fields in the optical regime. Based on stellar radial density profiles, we estimate distances of 1043 ± 36 pc (L1578) and 938 ± 49 pc (L1607), which are compared to the distances obtained from the 3D dust-reddening maps of the sky, and the results are found to be consistent. Extinction mapping using the PNICER method yields average visual extinctions of ∼1.7 and ∼1.4 mag, with corresponding hydrogen column densities of ∼1.6 × 10 21 cm −2 and ∼1.3 × 10 21 cm −2 for L1578 and L1607, respectively. From Herschel SPIRE observations, we derive mean dust temperatures of 13.5 K (L1578) and 14.0 K (L1607), and column densities consistent with extinction-based estimates. For L1578, an elliptical fit to the central clump yields a position angle of ∼−35° and a mass of ∼35 M ⊙ ; the virial parameter is found to lie in the range 4.8–5.9, indicating a gravitationally unbound structure. Polarimetric observations show mean degrees of polarization of 3.36% ± 0.05% (L1578) and 2.84% ± 0.06% (L1607), with well-aligned polarization angles (∼149° and ∼155°, respectively). The polarization vector maps exhibit ordered magnetic fields in the cloud envelopes, closely aligned with the Galactic plane. L1578 shows no observational evidence of ongoing star formation, while further investigation is needed to assess the star-forming status of L1607.

ABSTRACT The ability to make accurate determinations of planetary parameters is inextricably linked to measuring physical parameters of the host star, in particular the stellar radius. In this paper, we fit the stellar spectral energy distributions of exoplanet hosts to measure their radii, making use of only archival photometry, the ${\it Gaia}$ parallaxes, and ${\it Gaia}$ extinction maps. Using the extinction maps frees us of the degeneracy between temperature and extinction, which has plagued this method in the past. The resulting radii have typical random uncertainties of about 2 per cent. We perform a quantitative study of systematic uncertainties affecting the methodology and find they are similar to, or smaller than, the random ones. We discuss how the stellar parameters can be used to derive the properties of both transiting exoplanets, and those where only a radial-velocity curve is available. We then explore in detail the improvements the method makes possible for the parameters of the PanCET sample of transiting planets. For this sample we find the best literature measurements of the planetary radii have mean uncertainties about 40 per cent larger than those presented here, with the new measurements achieving precisions of 2 per cent in radius and 10 per cent in mass. In contrast to much recent work, these transiting exoplanet parameters are derived without using theoretical models of stellar interiors, freeing them of the assumptions those models contain and any priors for stellar age. As the data used are available for the whole sky, the method can be used for self-consistent measurements of the planetary parameters of a very large fraction of known exoplanets.

Abstract We present a new two-dimensional (2D) map of total Galactic extinction, $A_\mathrm{V}$, across the entire dust half-layer from the Sun to extragalactic space for Galactic latitudes $|b| > 13\degr$, as well as a three-dimensional (3D) map of $A_\mathrm{V}$ within 2~kpc of the Sun.
These maps are based on $A_\mathrm{V}$ and distance estimates derived from a dataset, which utilizes {\it Gaia} Data Release 3 parallaxes and multi-band photometry for nearly 100 million dwarf stars. We apply our own corrections to account for significant systematics in this dataset. Our 2D map achieves an angular resolution of 6.1~arcmin, while the 3D map offers a transverse resolution of 3.56~pc --- corresponding to variable angular resolution depending on distance --- and a radial resolution of 50~pc. In constructing these maps, we pay particular attention to the solar neighborhood (within 200~pc) and to high Galactic latitudes.
The 3D map predicts $A_\mathrm{V}$ from the Sun to any extended object within the Galactic dust layer with an accuracy of $\sigma(A_\mathrm{V}) = 0.1$~mag. The 2D map provides $A_\mathrm{V}$ estimates for the entire dust half-layer up to extragalactic distances with an accuracy of $\sigma(A_\mathrm{V}) = 0.07$~mag. We provide $A_\mathrm{V}$ estimates from our maps for various classes of extended celestial objects \textbf{with angular sizes primarily in the range of 2--40~arcmin}, including 19,809 galaxies and quasars, 170 Galactic globular clusters, 458 open clusters, \textbf{and several hundreds molecular clouds from two lists}. We also present extinction values for 8,293 Type Ia supernovae. Comparison of our extinction estimates with those from previous maps and literature sources reveals systematic differences, indicating large-scale spatial variations in the extinction law and suggesting that earlier 2D reddening maps based on infrared dust emission tend to underestimate low extinction values.

We present a homogeneous catalogue of verified 2MASX galaxies in high extinction areas that is complete to a Galactic extinction-corrected magnitude of łe 11 It covers the low Galactic latitudes ($|b| called Zone of Avoidance (ZoA), and areas of high foreground extinctions ( at higher latitudes. This catalogue supersedes the previously presented bright 2MZoA catalogue, which was only complete to łe 11 It fully complements the 2MASS Redshift Survey (2MRS) galaxy catalogue, which has the same magnitude limit but excludes high extinction regions. The combination of the two catalogues, the extended 2MRS or e2MRS, is a uniquely whole sky redshift survey of galaxies and forms a sound basis for studies of large-scale structures, cosmic flow fields, and extinction across the ZoA. The catalogue presented here comprises 6899 galaxies, with 6757 galaxies at low latitudes and 142 galaxies in highly obscured high-latitude areas. The completion rate in redshifts is almost 75%. The catalogue is complete up to star density levels of at least log N_*/ deg ^2 < 4.3, but the completion rate of the fainter part is affected by foreground extinction at all levels. This can be rectified by using a diameter-dependent extinction correction, which adds 605 highly obscured but apparently faint galaxies (with and łe 11 to the sample. This extended sample shows good completion rates with extinction up to at least $ Omission of such a diameter-dependent extinction correction may lead to a biased flow field even at intermediate extinction values as found in the 2MRS survey. As in our previous investigations, we recommend a correction factor of f=0.86 be applied to the extinction maps, and we find it to be independent of Galactic longitudes or latitudes.

Abstract Dust plays a critical role in the study of the interstellar medium (ISM). Extinction maps derived from optical surveys often fail to capture regions with high column density due to the limited photometric depth in optical wavelengths. To address these limitations, we developed the XPNICER method based on near-infrared (NIR) photometric survey data. This method combines the previously established PNICER and Xpercentile techniques, enabling effective mitigation of foreground contamination and improved handling of complex dust structures in the Galactic plane, which thus can provide more accurate extinction estimates, particularly in highly obscured regions. By applying XPNICER to the Galactic Plane Survey from the UKIRT Infrared Deep Sky Survey, we have generated a series of two-dimensional (2D) dust extinction maps that span roughly ∼1800 deg2 of the Galactic plane (0○ ≲ l ≲ 110○ and 140○ ≲ l ≲ 232○, |b| ≲ 5○). These maps, with spatial resolutions between 30” and 300”, can trace extinction up to AV ∼ 30−40 mag. This new approach offers higher spatial resolution and better detection of high-extinction regions compared to previous large-scale dust-based maps of the Galactic plane, providing an independent and complementary measure of dust column densities.

Abstract While plane-of-sky magnetic field observations in molecular clouds are now common, observations of their line-of-sight magnetic field remain limited. To address this issue, M. Tahani et al. developed a technique based on Faraday rotation. The technique incorporates an ON–OFF approach to identify the rotation measure induced by the magnetic fields associated with the cloud. The upcoming abundance of observations of Faraday rotation from the Square Kilometre Array and its pathfinders necessitates robustly tested software to automatically obtain line-of-sight magnetic fields of molecular clouds. We developed software, called MC-BLOS (for molecular cloud line-of-sight magnetic field; DOI:10.5281/zenodo.15338512), to carry out the technique in an automated manner. The software’s inputs are Faraday rotation of point sources, maps of extinction or column density, results from chemical evolution code, and a parameter file that allows the user to specify the cloud name or other parameters pertaining to the technique. For each cloud, the software invokes a set of predefined initial parameters such as density, temperature, and surrounding boundary, which the user can modify. The software then runs the technique automatically, outputting line-of-sight magnetic field maps and tables (including uncertainties) at the end of the process. MC-BLOS generates diagnostic files for result evaluation and input parameter refinement, allowing for expert judgment in parameter selection. We have tested the software on previously published clouds, and the results are consistent within the reported uncertainty range. This software will facilitate the analysis of forthcoming observations of Faraday rotation, enabling a better understanding of the role of magnetic fields in molecular cloud dynamics and star formation.

Abstract Although interstellar dust extinction serves as a powerful distance estimator, the solar system’s location within the Galactic plane complicates distance determinations, especially for molecular clouds (MCs) at varying distances along the line of sight (LoS). The presence of complex extinction patterns along the LoS introduces degeneracies, resulting in less accurate distance measurements to overlapping MCs in crowded regions of the Galactic plane. In this study, we develop the CUSUM-based Jump-point Analysis for Distance Estimation (CU-JADE), a novel method designed to help mitigate these observational challenges. The key strengths of CU-JADE include: (1) sensitivity to detect abrupt jumps in Distance– A λ ( D – A ) data sets, (2) minimal systematic errors as demonstrated on both mock and observed data, and (3) the ability to combine CUSUM analysis with multiwavelength data to improve the completeness of distance measurements for nearby gas structures, even for extinction values as low as Δ A V ≳ 0.15 mag. By combining CO survey data with a large sample of stars characterized by high-precision parallaxes and extinctions, we uncovered the multilayered molecular gas distribution in the high-latitude Cepheus region. We also determined accurate distances to MCs beyond the Cygnus Rift by analyzing the intricate structure of gas and extinction within the Galactic plane. Additionally, we constructed a full-sky 3D extinction map extending to 4 kpc, which provides critical insights into dense interstellar medium components dominated by molecular hydrogen. These results advance our understanding of the spatial distribution and physical properties of MCs across the Milky Way.

Abstract G116.6 - 26.1 has been newly discovered as a supernova remnant (SNR) through the SRG/eROSITA X-ray survey, located in a high-latitude, low-density region. Its distance and progenitor nature remain uncertain. Our objective is to explore the surroundings of SNR G116.6 - 26.1 to determine its distance and surrounding environmental conditions. High-resolution and sensitive HI observations around G116.6 - 26.1 from the Five-hundred-meter Aperture Spherical radio Telescope (FAST), with an RMS level of 1.0 mJy beam$^{-1}$, were utilized to study the distribution of cold gas in this SNR region. Furthermore, an extinction map for this area helps estimate the distance to G116.6 - 26.1. We identified four HI structures associated with G116.6 - 26.1 in the local standard of rest (LSR) velocity range -133.9 to -63.9 km s$^{-1}$: clouds A1, B1, B2, and C1. Together with other components in the A-series and the C-series, they form a large cloud that exhibits a cavity in this SNR region. The A- and C-series share similar velocities, while B1 and B2, both in the SNR area, differ by 10 - 30 km s$^{-1}$. The X-ray morphology displays deformation features that align spatially with the \HI\ structure C1 boundary interface. Using three-dimensional (3D) extinction data, we estimate the cloud's distance to be 2.7$^{+3.18}_{-0.50}$ kpc, suggesting that G116.6 $-$ 26.1 exploded within an \HI\ cloud beyond the Galactic plane, about 2.7 kpc away.

ABSTRACT This study presents a comprehensive statistical analysis of the star cluster AFGL 6366S, focusing on its fundamental, structural and dynamical properties. The membership analysis identifies 142 member stars for the cluster with a mean parallax of 0.389 $\pm$ 0.006 mas and mean proper motions of 0.315 $\pm$ 0.014 mas yr$^{-1}$ in right ascension and −2.005 $\pm$ 0.012 mas yr$^{-1}$ along declination. The cluster is very young, with an estimated age of 3.02 $\pm$ 0.14 Myr, partially embedded in its natal cloud and shows a visual extinction of 2.50 $\pm$ 0.35 mag. It represents a metal-rich environment with [Fe/H] = 0.35 $\pm$ 0.02. The structural parameters of the cluster are: central density = 1.10 $\pm$ 0.27 stars pc$^{-2}$, core radius = 2.17 $\pm$ 0.68 pc, tidal radius = 7.45 $\pm$ 0.87 pc, half-mass radius = 2.16 $\pm$ 0.37 pc and background density = 0.025 $\pm$ 0.009 stars pc$^{-2}$. The cluster is located at a distance of 3.00 $\pm$ 0.34 kpc and its Galactic orbit analysis classifies the cluster as a thin-disc object in the Milky Way, lying outside the solar circle. The cluster also exhibits a fractal, sub-structured morphology indicating that it is not yet dynamically relaxed and its structure as well as stellar distribution are likely evolving. The visual extinction map of the cluster region reveals differential reddening, an elongated filament ($\sim$ 3.01 pc in length) and 9 dense clumps $\le$ 0.5 pc in radii. The region likely exhibits the characteristics of hierarchical star formation.

The spectral width and the center wavelength of the ultraviolet (UV) absorption bump measured for at least two z≃7 galaxies were found to differ significantly from Milky Way (MW) values. A decrease in the width by ∼ 45% and a positive shift of the center by ∼ 70-80 Å were measured. Within the MW, the bump amplitude and width do vary; however, such a narrow bump has never been observed and no variability of the peak position has been convincingly found. On the other hand, links have recently been detected between both the amplitude and the width of the bump and the strength of several diffuse interstellar absorption bands (DIBs). The links were found to be limited to the so-called σ-type DIBs and their detection to be strongly favored if the data were limited to monocloud-type lines of sight (LOSs), selected according to 3D maps of dust extinction. We aim to extend the study of the links between MW DIBs and UV bump parameters to the center wavelength of the bump and to the ratio between the bump amplitude and the underlying continuum, and to compare the characteristics of the MW variations in the bump parameters to values at a high redshift. We used published catalogs of cross-matched measurements of DIBs and reddening law parameters. We assigned monocloud flags to all LOSs. We focused on the strong σ-type DIBs at 5780 and 6284Å , and ζ-type DIBs at 5797 and 5850Å, and searched for trends linking the bump parameters to the DIB strength normalized to the reddening. Similarly to the case of the bump amplitude and width, the center wavelength of the bump is found to react to the abundance of σ-type DIB carriers and to be insensitive to the abundance of the ζ-type DIB carriers, which dominate in dense and UV-shielded cloud cores. A strong abundance of σ carriers induces a shift of the bump peak position to longer wavelengths and a decrease in its width. The variability range for these two parameters in the MW is about half the difference between average MW values and values in the distant galaxies. In the MW, an increase in the abundance of σ carriers also corresponds to an increase in the bump amplitude and in the ratio between the amplitude and the underlying continuum. In the case of the MW, these results reinforce the hypothesis of the existence of individual types of hydrocarbon molecules that are simultaneously responsible for DIBs and part of the UV bump. They show that the majority of species responsible for narrow and positively shifted bumps in distant galaxies have a link with (or are) those producing the σ DIBs and the long-wavelength part of the bump in the MW, and that, on the contrary, species producing the short-wavelength part of the bump in the MW are of a different nature and are absent along the paths to the regions of those distant galaxies that contribute most to the UV emission. These results are based on a limited number (≃ 95) of MW LOSs. More measurements of the reddening curve obtained with a space borne UV spectrograph and more massive DIB measurements with ground-based spectrographs would impose better constraints on the relationships between DIBs and UV bumps. Identifications of DIB carriers would shed light on their formation and the origin of the UV bump in the MW and distant galaxies.