arXiv subjects

S. Hutschenreuter

Publications and source records attributed to S. Hutschenreuter.

10 recordsLinked to original sources

arXiv2026

HURACAN: A comparison of stellar and interstellar proper motions inside L1688

The assumption that molecular clouds are kinematically coupled to the young stellar populations forming within them is observationally still poorly constrained. With the transverse component $v_{\textrm{t}}$ of the interstellar medium (ISM) motion being largely unknown, the three-dimensional kinematic state of even the closest clouds remains incomplete. We provide the first direct measurement of the transverse motion of the ISM inside the Ophiuchus cloud L1688 and compare it with the kinematics of the surrounding young stellar populations. The measurement was obtained using intensity-based image registration applied to archival data, allowing us to generate a proper motion field of the studied regions and determine the cloud's bulk motion, $(μ_{α^*},μ_δ)^{\mathrm{ISM}}_{\mathrm{median}}=(-3.0, -24.1)$ mas yr$^{-1}$. This motion differs from the kinematics of the youngest population in Upper Scorpius by $3\pm1$ km s$^{-1}$, highlighting the possibility of a bias when using stars as a proxy for the ISM motion near star-forming regions. By comparing the cloud's motion with that of the youngest stellar population in the region and the B-star Oph S1 located within the cloud, we find that stellar feedback must have dynamically shaped the motion of the ISM over the last few million years. Furthermore, by studying a shell-like ISM structure appearing in L1688, we find evidence suggesting that this object is likely neither a typical Herbig-Haro object nor a supernova remnant, with its origin remaining a mystery. Our results demonstrate that archival and future high-resolution near-infrared observations can and will continue to enable measurements of ISM transverse motions in nearby clouds, opening a new window for studying ISM dynamics that is not accessible when using radial velocities alone.

astro-ph.GA↗

arXiv2026

Accelerated gas flow along Ophiuchus B44 filament: Breaking Position-Position-Velocity degeneracy

(Abridged) Stellar feedback from massive stars in the Upper-Sco has been proposed to have reshaped the gas in the nearby Ophiuchus complex. In this framework, feedback organizes the gas into two filament types based on their orientation relative to the source of feedback: radial (R-type) filaments, aligned radially to the massive stars, and tangential (T-type) filaments, which are orthogonal to the feedback direction. A key prediction of this scenario is that gas within R-type filaments should flow longitudinally away from the massive stars. In this paper, we test this scenario by measuring the three-dimensional gas flow inside the potential R-type filament B44, combining the 3D orientation of the filament from Gaia-based 3D dust maps with radial velocities from CO observations. We find that gas flows longitudinally along the B44 filament away from the massive stars in Upper-Sco with both tracers yielding consistent velocity fields. This result confirms B44 is a R-type filament formed by stellar feedback from Sco-Cen with an implied filament assembly timescale of $\sim$3~Myr, well within the age of the Upper-Sco massive stars. Moreover, we find that the gas motion along B44 and away from the massive stars is accelerated with $a\sim$1.8~km/s/Myr ($\sim 6 \times 10^{-11}$~m/s$^2$). This acceleration is compatible with the accelerations recorded along the Sco-Cen cluster chains over the past $\sim$15~Myr, indicating that B44 is likely a present-day, gas-phase counterpart of the same feedback-driven process that produced those stellar sequences. We further find evidence for a shock at the wind-facing head of the filament, with a deprojected flow Mach number of $\sim$2 and a matching density jump. Our findings demonstrate that Gaia 3D dust maps can lift the line-of-sight ambiguity intrinsic to PPV spectral data, enabling direct deprojection of the gas velocity field in coherent filaments.

astro-ph.GA↗

arXiv2026

EMU discovery of Thunder: a bow-shock PWN powered by PSR J1631-4722 escaping Nimbus SNR (G336.7+0.5)

We report the discovery of a bow-shock pulsar wind nebula (PWN), dubbed Thunder, powered by the radio pulsar PSR J1631-4722 and projected within the Galactic supernova remnant (SNR) G336.7+0.5 (Nimbus). The system was first identified in observations from the Australian Square Kilometre Array Pathfinder (ASKAP) Evolutionary Map of the Universe (EMU) survey and further characterised using MeerKAT Galactic Plane Survey data together with follow-up observations at 5.5 and 9 GHz obtained with the Australia Telescope Compact Array (ATCA). Assuming a distance of 7 kpc, the radio images resolve an elongated ~80 arcsec (2.7 pc) cometary nebula, indicative of a high velocity pulsar. An X-ray counterpart extending ~50 arcsec (1.7 pc) is detected in archival XMM-Newton data. The flat radio spectrum ($α$ = -0.27 $\pm$ 0.05) and hard X-ray photon index ($Γ$ = 1.6 $\pm$ 0.4) indicate synchrotron emission from relativistic particles injected in the pulsar wind. Polarisation analysis reveals a highly ordered magnetic field aligned with the nebular flow, with fractional polarisation reaching up to 30% in the tail. An equipartition estimate gives a PWN magnetic-field strength of Beq $\approx$ 54-140 $μ$G. Pulsar timing over a ~2.2 yr baseline reveals strong timing noise and a small spin glitch with amplitude $Δν/ν$ = 1.10$\times$10$^{-8}$. The SNR shows no clear diffuse X-ray counterpart. The morphology and multiwavelength properties of the Nimbus-Thunder system, along with evolutionary models, constrain the system's age to approximately 30-45 kyr, placing the remnant in the late Sedov phase, approaching the transition to the radiative stage.

astro-ph.HE↗

arXiv2025

The velocity field of the Scorpius-Centaurus OB association

We present a non-parametric reconstruction of the three-dimensional velocity field of the Scorpius-Centaurus OB association (Sco- Cen). Using Gaia DR3 astrometry and radial velocities, we infer the velocity field using information field theory on a 70 x 70 x 50 grid at 3 pc resolution. Our model suggests the existence of a primary stellar velocity field with a secondary field that accounts for an additional young kinematic component in Upper Scorpius and Lupus. We find clear tracers of a feedback-driven expansion of the association, while Galactic rotation appears to play a subordinate role. The results confirm the existence of cluster chains and reveal coherent large-scale expansion with characteristic speeds of 1-2 km s$^{-1}$ and local maxima of about 10 km s$^{-1}$. Power spectra indicate an excess of small-scale structure and slopes shallower than Kolmogorov, consistent with energy injection from stellar feedback. Maps of the divergence reveal net positive values, implying an approximate dispersal timescale of 10-15 Myr. A comparison with molecular gas in Lupus and Ophiuchus shows broadly consistent patterns but systematic velocity offsets of several km s$^{-1}$, suggesting partial decoupling for optically visible young stars and gas. The framework presented provides a physically motivated description of the Sco-Cen velocity field and a basis for quantifying the dynamical state and feedback history of OB associations in the local Galaxy.

astro-ph.GA↗

arXiv2025

Survey of Profile Parameters of the $6196 Å$ Diffuse Interstellar Band. From Uniform Profiles to Doppler Splitting and Blueshifts

The diffuse interstellar band (DIB) at 6196 A exhibits notable profile variations across the Milky Way. This study addresses three open issues: the unusual broadening of the DIB profile towards Upper Sco (USco), the lack of profile variations towards stars near $η$ Car, and the origin of the blueshift observed in Sco OB1. Using archival spectra of 453 early-type stars across the Galactic disk and in its proximity, we created a catalogue of the DIB's profile parameters. Our analysis identified Doppler-split components within the DIB profiles across most regions with no evidence for these splits being able to account for the observed broadening (23 km/s) in USco or other regions such as Orion, Vela OB2, and Melotte 20 ($α$ Per cluster). We propose that neither the ages of the studied stellar populations nor the distances between clusters and nearby clouds significantly contribute to the broadening. However, we detect a gradient in the full width at half maximum within the Sco-Cen and Orion regions, where broadening decreases with distance from the star-forming centres. This result points to a possible connection between the DIB broadening and star formation (likely via the impact of recent supernovae). Regarding the Carina Nebula, we confirm the lack of DIB profile variations in a small region near $η$ Car, although an adjacent southern area exhibits significant variations, comparable to those in USco. In addition to the Carina Nebula, we find that the Rosette Nebula and NGC 6405 also show consistently narrow profiles (<20 km/s) with minimal deviations from the median over spatial scales of a few parsecs. Finally, regarding the origin of the blueshift observed in Sco OB1, we used a comparison with the Lagoon Nebula and argue that the most natural explanation is the presence of an unresolved kinematic component in the profile of the DIB, shifting the measured centre of the band.

astro-ph.GA↗

arXiv2025

Direct measurement of ISM proper motion with image registration

To date, quantification of the on-sky motion for interstellar clouds have relied on proxies such as young stellar objects (YSO) and masers. We present the first direct measurement of an interstellar cloud proper motion using the VISTA Star Formation Atlas (VISIONS) multi-epoch infrared images of the Corona Australis star-forming region. Proper motions are extracted by tracking the morphology of extended structures in the cloud complex based on image registration techniques implemented in SimpleITK. Our determined values ($μ_{α^*} \sim +15$ mas/yr, $μ_δ \sim -30$ mas/yr) are in good agreement with those obtained for YSOs and young stellar clusters in the region. This study demonstrates the potential of image registration for directly mapping the kinematics of nearby molecular clouds, opening a new window into the study of cloud dynamics.

astro-ph.GA↗

arXiv2024

Towards a complete picture of the Sco-Cen outflow

Previous studies have shown strong evidence that the Sun is crossing an outflow originating from the Sco-Cen OB association. Understanding this outflow's origin and structure illuminates how massive star formation shapes the interstellar medium (ISM) and helps predict future Galactic conditions affecting our Solar System. We analysed H I emission and optical ISM absorption lines towards 47 early-type stars around the Upper Sco region to refine the map of the Sco-Cen outflow. Combined with data for nearby stars, we find that the outflow has at least two components: a faster, low-density component traced by Ca II, and a slower, possibly lower-density component traced by Mg II and Fe II in the UV that is passing through the Earth. A constant flow model successfully describes both components with $(l,b,|\vec{v}|) = (335.4^{\circ}, -6.8^{\circ}, 14.0 \,\,\textrm{km}\,\textrm{s}^{-1})$ and $(305.5^{\circ}, +17.6^{\circ}, 21.2\,\,\textrm{km}\,\textrm{s}^{-1})$, respectively. The origin of the faster component points towards the Sco-Cen 15 Myr population, which is consistent with the origin of the slower component within 2 $σ$. A simple model comparison indicates that a constant flow is favoured over a spherical flow geometry, implying an extended distribution of feedback sources within Sco-Cen. We also found that a poorly studied 25 pc long H I cloud at a distance of 107 pc belongs to the established Sco-Cen flow.

astro-ph.GA↗

arXiv2023

RMTable2023 and PolSpectra2023: standards for reporting polarization and Faraday rotation measurements of radio sources

Faraday rotation measures (RMs) have been used for many studies of cosmic magnetism, and in most cases having more RMs is beneficial for those studies. This has lead to development of RM surveys that have produced large catalogs, as well as meta-catalogs collecting RMs from many different publications. However, it has been difficult to take full advantage of all these RMs as the individual catalogs have been published in many different places, and in many different formats. In addition, the polarization spectra used to determine these RMs are rarely published, limiting the ability to re-analyze data as new methods or additional observations become available. We propose a standard convention for RM catalogs, RMTable2023, and a standard for source-integrated polarized spectra of radio sources, PolSpectra2023. These standards are intended to maximize the value and utility of these data for researchers and to make them easier to access. To demonstrate the use of the RMTable2023 standard, we have produced a consolidated catalog of 55 819 RMs collected from 42 published catalogs.

astro-ph.IM↗

arXiv2023

Detection of magnetic fields in the circumgalactic medium of nearby galaxies using Faraday rotation

Context. The existence of magnetic fields in the circumgalactic medium (CGM) is largely unconstrained. Their detection is important as magnetic fields can have a significant impact on the evolution of the CGM and, in turn, the fields can serve as tracers for dynamical processes in the CGM. Aims. With Faraday rotation of polarised background sources, we aim to detect a possible excess of the rotation measure in the surrounding area of nearby galaxies. Methods. We use 2,461 residual rotation measures (RRMs) observed with the LOw Frequency ARray (LOFAR), where the foreground contribution from the Milky Way is subtracted. The RRMs are then studied around a subset of 183 nearby galaxies that was selected by apparent $B$-band magnitude. Results. We find that, in general, the RRMs show no significant excess for small impact parameters (i.e. the perpendicular distance to the line of sight). However, if we only consider galaxies at higher inclination angles and sight lines that pass close to the minor axis of the galaxies, we find significant excess at impact parameters of less than 100 kpc. The excess in |RRM| is 3.7 $\rm rad\,m^{-2}$ with an uncertainty between $\pm 0.9~\rm rad\,m^{-2}$ and $\pm 1.3~\rm rad\,m^{-2}$ depending on the statistical properties of the background (2.8$σ$-4.1$σ$). With electron densities of ~$10^{-4}~\rm cm^{-3}$ this suggests magnetic field strengths of a few tenths of a micro Gauss. Conclusions. Our results suggest a slow decrease of the magnetic field strength with distance from the galactic disc such as expected if the CGM is magnetised by galactic winds and outflows.

astro-ph.GA↗

arXiv2021

Studying Bioluminescence Flashes with the ANTARES Deep Sea Neutrino Telescope

We develop a novel technique to exploit the extensive data sets provided by underwater neutrino telescopes to gain information on bioluminescence in the deep sea. The passive nature of the telescopes gives us the unique opportunity to infer information on bioluminescent organisms without actively interfering with them. We propose a statistical method that allows us to reconstruct the light emission of individual organisms, as well as their location and movement. A mathematical model is built to describe the measurement process of underwater neutrino telescopes and the signal generation of the biological organisms. The Metric Gaussian Variational Inference algorithm is used to reconstruct the model parameters using photon counts recorded by the neutrino detectors. We apply this method to synthetic data sets and data collected by the ANTARES neutrino telescope. The telescope is located 40 km off the French coast and fixed to the sea floor at a depth of 2475 m. The runs with synthetic data reveal that we can reliably model the emitted bioluminescent flashes of the organisms. Furthermore, we find that the spatial resolution of the localization of light sources highly depends on the configuration of the telescope. Precise measurements of the efficiencies of the detectors and the attenuation length of the water are crucial to reconstruct the light emission. Finally, the application to ANTARES data reveals the first precise localizations of bioluminescent organisms using neutrino telescope data.

physics.ao-ph↗