Related papers: A Molecular Spiral Arm in the Far Outer Galaxy

Aims. We aim to understand the unexpected presence of mm-wave molecular absorption at -200 \kms $< {\rm v} < -140$ \kms\ in a direction that is well away from regions of the Galactic bulge where CO emission at such velocities is prominent.…

We report the first results from a survey for 1665, 1667, and 1720 MHz OH emission over a small region of the Outer Galaxy centered at $l \approx 105.0\deg , b \approx +1.0\deg$ . This sparse, high-sensitivity survey ($\Delta Ta \approx…

IRAM 30m 12CO(1-0) and 12CO(2-1) HERA observations are presented for the ram-pressure stripped Virgo spiral galaxy NGC 4522. The CO emission is detected in the galactic disk and the extraplanar gas. The extraplanar CO emission follows the…

As a relatively young and bright population and the archetype of standard candles, classical Cepheids are an ideal population on which to trace the non-axisymmetric structure in the young stellar disk to large distances. We used the new…

Context: The bulk of the Molecular gas in the Central Molecular Zone (CMZ) of the Galactic center region shows warm kinetic temperatures, ranging from $>20$ K in the coldest and densest regions (n$\sim 10^{4-5}$ cm$^{-3}$) up to more than…

We investigate the morphology and kinematics of the Galactic spiral structure based on a new sample of O- and early B-type stars. We select 6,858 highly confident OB star candidates from the combined data of the VST Photometric H$\alpha$…

The Leading Arm is a tidal feature that is in front of the Magellanic Clouds on their orbit through the Galaxy's halo. Many physical properties of the Leading Arm, such as its mass and size, are poorly constrained because it has few…

We use hydrodynamical simulations to construct a new coherent picture for the gas flow in the Central Molecular Zone (CMZ), the region of our Galaxy within $R\leq 500\, \mathrm{pc}$. We relate connected structures observed in $(l,b,v)$ data…

Giant Molecular Filaments are opportune locations in our Galaxy to study the star-forming interstellar matter and its accumulation on spatial scales comparable to those now becoming available for external galaxies. We mapped the emission of…

Three dimensional (3D) distribution of the volume-density molecular fraction, defined by fmol_rho=rho_H2/(rho_HI + rho_H2), is studied in the Milky Way Galaxy. The molecular front appears at galacto-centric distance of R \sim 8 kpc, where…

The Milky Way is a spiral galaxy with the Schechter characteristic luminosity $L_*$, thus an important anchor point of the Hubble sequence of all spiral galaxies. Yet the true appearance of the Milky Way has remained elusive for centuries.…

We explore the longitude-velocity distribution of 6.7-GHz methanol masers in the context of the inner structure of our Galaxy. We analyse the correlation in velocities within this distribution and identify density enhancements indicating…

We report about high spatial resolution observations made with the IRAM interferometer of the CO emission from a 1.1x1.1 kpc plane-of-sky field on a spiral arm of Messier 81. With a beam of 5''(90 pc), we identify 6 giant molecular cloud…

A new model for the luminosity distribution in the inner Milky Way is found, using a non-parametric penalized maximum-likelihood algorithm to deproject a dereddened COBE/DIRBE L-band map of the inner Galaxy. The model is also constrained by…

The height of the Milky Way diffusion halo, above which cosmic-rays can freely escape the galaxy, is among the most critical, yet poorly known, parameters in cosmic-ray physics. Measurements of radioactive secondaries, such as $^{10}$Be or…

We present medium-resolution spectroscopy of a sample of stars in the second Galactic quadrant selected from the literature because their colours suggest that they are moderately-reddened early-type stars at very large distances. From the…

We present distances to 56 molecular clouds within $10\degr \leq l \leq 20\degr$ and $|b| \leq 5.25\degr$ from the Milky Way Imaging Scroll Painting (MWISP) $^{12}$CO survey, 47 of which are first-time determinations. The molecular clouds…

Recent observational advances, such as Gaia DR3 GSP-Spec, have highlighted the potential of chemical abundances in tracing and revealing the structure of spiral arms. Building on these studies, we aim to trace the Milky Way's inner spiral…

Using spectral-line observations of HNCO, N2H+, and HNC, we investigate the kinematics of dense gas in the central ~250 pc of the Galaxy. We present SCOUSE (Semi-automated multi-COmponent Universal Spectral-line fitting Engine), a line…

We present the highest resolution (1") $^{12}$CO(1-0) observations of molecular gas in the dwarf starburst galaxy NGC 625, to date, obtained with ALMA. Molecular gas is distributed in discrete clouds within an area of $0.4$ kpc$^2$ and does…