We analyzed the data of Stokes $I$, $Q$, and $U$ in C- and X-bands and investigated the large-scale magnetic field structure of NGC 3627. The polarization intensity and angle in each band were derived using Stokes $Q$ and $U$ maps. The rotation measure was calculated using the polarization-angle maps. Moreover, the magnetic field strength was calculated by assuming energy equipartition with the cosmic ray electrons. The structure of the magnetic field was well aligned with the spiral arms, which were consistent with those in the former studies. We applied the magnetic vector reconstruction method to NGC 3627 to derive a magnetic vector map, which showed that northern and southern disks were dominant with inward and outward magnetic vectors, respectively. Furthermore, we discussed the large-scale structure of the magnetic field in NGC 3627 and observed that the structure is bi-symmetric spiral in nature, and that the number of magnetic field mode is $ m_{\rm B} = 1 $ in outer region of galaxy. In addition, NGC 3627 has a mode of two spiral arms that were clearly visible in an optical image. The ratio of the mode of spiral arms to that of magnetic field is 2:1. In terms of NGC 3627, the large-scale magnetic field may be generated via the parametric resonance induced by the gravitational potential of the spiral arms.
We studied large-scale magnetic field reversals of a galaxy based on a magnetic vector map of NGC6946. The magnetic vector map was constructed based on the polarization maps in the C and X bands after the determination of the geometrical orientation of a disk with the use of an infrared image and the velocity field, according to the trailing spiral arm assumption. We examined the azimuthal variation of the magnetic vector and found that the magnetic pitch angle changes continually as a function of the azimuthal angle in the inter-arm region. However, the direction of the magnetic field had $18…
We present a comparative study of CO and polycyclic aromatic hydrocarbon (PAH) emission toward a region including the massive star-forming regions of NGC 6334 and NGC 6357. We use the NANTEN $^{12}$CO($J$ = 1--0) data and the $AKARI$ 9 $μ$m All-Sky diffuse map in order to evaluate the calibration accuracy of the $AKARI$ data. We confirm that the overall CO distribution shows a good spatial correspondence with the PAH emission, and their intensities exhibit a good power-law correlation with a spatial resolution down to 4$'$ over the region of 10$^\circ$$\times$10$^\circ$. We also reveal poorer …
We present the results of CO(J=3-2) on-the-fly mappings of two nearby non-barred spiral galaxies NGC 628 and NGC 7793 with the Atacama Submillimeter Telescope Experiment at an effective angular resolution of 25". We successfully obtained global distributions of CO(J=3-2) emission over the entire disks at a sub-kpc resolution for both galaxies. We examined the spatially-resolved (sub-kpc) relationship between CO(J=3-2) luminosities (L'CO(3-2)) and infrared (IR) luminosities (LIR) for NGC 628, NGC 7793, and M 83, and compared it with global luminosities of JCMT Nearby Galaxy Legacy Survey sample…
NGC 5548 has been well spectroscopically monitored for reverberation mapping of the central kinematics by 19 campaigns. Using the maximum entropy method in this Letter, we build up a high-quality velocity-delay map of the H$β$ emission line in the light curves of the continuum and the line variations observed between 2015-2016. The map shows the response strength and lags of the velocity fields of the H$β$ emitting regions. The velocity-delay structure of the map is generally symmetric, with strong red and blue wings at time lag $τ\leq 15$ days, a narrower velocity distribution at $τ\geq 15$ d…
We use NH3 inversion transitions to trace the dense gas in the NGC 1333 region of the Perseus molecular cloud. NH3(1,1) and NH3(2,2) maps covering an area of 102 square arcminutes at an angular resolution of ~3.7" are produced by combining VLA interferometric observations with GBT single dish maps. The combined maps have a spectral resolution of 0.14 km/s and a sensitivity of 4 mJy/beam. We produce integrated intensity maps, peak intensity maps and dispersion maps of NH3(1,1) and NH3(2,2) and a line-of-sight velocity map of NH3(1,1). These are used to derive the optical depth for the NH3(1,1) …
Using velocity tagging we have detected hydrogen from NGC 5426 falling onto its interacting partner NGC 5427. Our observations, with the GHaFaS Fabry-Perot spectrometer, produced maps of the two galaxies in Halpha surface brightness and radial velocity. We found emission with the range of velocities associated with NGC 5426 along lines of sight apparently emanating from NGC 5427, superposed on the velocity map of the latter. After excluding instrumental effects we assign the anomalous emission to gas pulled from NGC 5426 during its passage close to NGC 5427. Its distribution, more intense betw…
The large field and wavelength range of MUSE is well suited to mapping Galactic planetary nebulae (PN). The bright PN NGC 7009 was observed with MUSE on the VLT during the Science Verification of the instrument in seeing of 0.6". Emission line maps in hydrogen Balmer and Paschen lines were formed from analysis of the MUSE cubes. The measured electron temperature and density from the MUSE cube were employed to predict the theoretical hydrogen line ratios and map the extinction distribution across the nebula. After correction for the interstellar extinction to NGC 7009, the internal dust-to-gas …
We present the [CII] 157.7 micron map of galaxy NGC 7331 obtained with FIFI-LS on SOFIA. This map extends an existent Herschel/PACS observation of the central strip of the galaxy to encompass the entire molecular ring and much of the disk, including multiple spiral arms with intense far-IR emission. We also present Herschel archival data of the [NII] 205 micron line which covers a substantial part of the [CII] SOFIA observations and allows us to estimate the neutral fraction of the [CII] emission along the ring and disk of the galaxy. We find that the neutral fraction rises with the distance f…
Most of the galaxies in the Universe at present day are in groups, which are key to understanding the galaxy evolution. In this work we present a new deep mosaic of 1.2 x 1.0 square degrees of the group of galaxies centered on NGC 5018, acquired at the ESO VLT Survey Telescope. We use u, g, r images to analyse the structure of the group members and to estimate the intra-group light. Taking advantage of the deep and multiband photometry and of the large field of view of the VST telescope, we studied the structure of the galaxy members and the faint features into the intra-group space and we giv…
We report one of the first extragalactic observations of electron temperature variations across a spiral arm. Using MUSE mosaic observations of the nearby galaxy NGC 1672, we measure the [N II]5755 auroral line in a sample of 80 HII regions in the eastern spiral arm of NGC1672. We discover systematic temperature variations as a function of distance perpendicular to the spiral arm. The electron temperature is lowest on the spiral arm itself and highest on the downstream side. Photoionization models of different metallicity, pressure, and age of the ionizing source are explored to understand wha…
In this paper, we present BVRI imaging data of NGC 613. We use these data to determine the corotation radius of the bar, using the photometric phase crossing method. This method uses the phase angle of the spiral structure in several wavebands, and looks for a crossing between the blue (B) light and the redder wavebands (e.g., R or I). For NGC 613, we find two phase crossings, an outer phase crossing at 136 +/- 8 arcsec and an inner phase crossing at 16 +/- 8 arcsec. We argue that the outer phase crossing is due to the bar corotation radius, and from the bar length of $R_{\rm bar}=90.0\pm4.0$ …
We trace the evolution of the edge-on spiral galaxy NGC 3501, making use of its stellar populations extracted from deep integral-field spectroscopy MUSE observations. We present stellar kinematic and population maps, as well as the star formation history, of the south-western half of the galaxy. The derived maps of the stellar line-of-sight velocity and velocity dispersion are quite regular, show disc-like rotation, and no other structural component of the galaxy. However, maps of the stellar populations exhibit structures in the mass-weighted and light-weighted age, total metallicity and [Mg/…
Optical integral-field spectroscopy was used to investigate the planetary nebula NGC 3242. We analysed the main morphological components of this source, including its knots, but not the halo. In addition to revealing the properties ofthe physical and chemical nature of this nebula, we also provided reliable spatially resolved constraints that can be used for future photoionisation modelling of the nebula. The latter is ultimately necessary to obtain a fully self-consistent 3D picture of the physical and chemical properties of the object. The observations were obtained with the VIMOS instrument…
A fully-sampled and hitherto highest resolution and sensitivity observation of neutral hydrogen (HI) in the Leo Triplet (NGC 3628, M 65/NGC 3623, and M 66/NGC 3627) reveals six HI structures beyond the three galaxies. We present detailed results of the morphologies and kinematics of these structures, which can be used for future simulations. In particular, we detect a two-arm structure in the plume of NGC 3628 for the first time, which can be explained by a tidal interaction model. The optical counterpart of the plume is mainly associated with the southern arm. The connecting part (base) of th…
We used the Atacama Large Millimeter/submillimeter Array (ALMA) to map the CO(3-2) and the underlying continuum emissions around the type 1 low-luminosity active galactic nucleus (LLAGN; bolometric luminosity $\lesssim 10^{42}$ erg~s$^{-1}$) of NGC 1097 at $\sim 10$ pc resolution. These observations revealed a detailed cold gas distribution within a $\sim 100$ pc of this LLAGN. In contrast to the luminous Seyfert galaxy NGC 1068, where a $\sim 7$ pc cold molecular torus was recently revealed, a distinctively dense and compact torus is missing in our CO(3-2) integrated intensity map of NGC 1097…
The NGC 1333 IRAS 4A protobinary was observed in the 1.3 cm and 6.9 mm continuum and the ammonia and SiO lines, with an angular resolution of about 0.4 arcseconds. The continuum maps show the circumstellar structures of the two protostars, A1 and A2. The A1 system is brighter and more massive than the A2 system. The ratio of mass, including dense gas and protostar, is about 6. The properties of the circumstellar disks and outflows suggest that A1 may be younger than A2. The deflected part of the northeastern jet of A2 is bright in the SiO line, and the distance between the brightest peak and d…
We have mapped the extended narrow line region (ENLR) of NGC 3393 on scales of $r\lesssim4^{\prime\prime}$ ($\sim1\,$kpc) from the nucleus using emission line images of H$α\,\lambda6563$, [O III]$\lambda5007$, and [S II]$λ\lambda6717,6731$ taken with HST as part of the CHandra survey of Extended Emission line Regions in nearby Seyfert galaxies (CHEERS). By mapping these lines onto a spatially resolved Baldwin-Phillips-Terlevich (BPT) diagram, we investigate the impact of feedback from a Compton-thick AGN on its circumnuclear ISM. We find the expected Seyfert-like emission within the ionization…
The Virgo cluster of galaxies provides excellent conditions for studying interactions of galaxies with the cluster environment. Both the high-velocity tidal interactions and effects of ram pressure stripping by the intracluster gas can be investigated in detail. We extend our systematic search for possible anomalies in the magnetic field structures of Virgo cluster spirals in order to characterize a variety of effects and attribute them to different disturbing agents. Six angularly large Virgo cluster spiral galaxies (NGC4192, NGC4302, NGC4303, NGC4321, NGC4388, and NGC4535) were targets of a …
We used optical images acquired with the UVIS channel of the Wide Field Camera 3 on board of the Hubble Space Telescope to construct the first high-resolution extinction map in the direction of NGC 6440, a globular cluster located in the bulge of our Galaxy. The map has a spatial resolution of 0.5" over a rectangular region of about 160" X 240" around the cluster center, with the long side in the North-West/South-East direction. We found that the absorption clouds show patchy and filamentary sub-structures with extinction variations as large as $δ{\rm E}(B-V)\sim0.5$ mag. We also performed a f…
This work presents an extended, neutral Hydrogen emission map around Magellanic-type dwarf irregular galaxy (dIm) NGC 1569. In the Spring of 2010, the Robert C. Byrd Green Bank Telescope (GBT) was used to map a 9 degree x 2 degree region in HI line emission that includes NGC 1569 and IC 342 as well as two other dwarf galaxies. The primary objective for these observations was to search for structures potentially connecting NGC 1569 with IC 342 group members in order to trace previous interactions and thus, provide an explanation for the starburst and peculiar kinematics prevalent in NGC 1569. A…
We report on the extinction properties in the fields around the clusters NGC 1854, NGC 1856, and NGC 1858 in the bar of the Large Magellanic Cloud. The colour-magnitude diagrams of the stars in all these regions show an elongated red giant clump that reveals a variable amount of extinction across these fields, ranging from Av~0.2 to Av~1.9, including Galactic foreground extinction. The extinction properties nonetheless are remarkably uniform. The slope of the reddening vectors measured in the (V-I,V) and (B-I,B) colour-magnitude planes is fully in line with the Av/E(B-V)~5.5 value found in the…
We present the analysis of infrared (IR) observations of the planetary nebula NGC 40 together with spectral analysis of its [WC]-type central star HD 826. Spitzer IRS observations were used to produce spectral maps centred at polycyclic aromatic hydrocarbons (PAH) bands and ionic transitions to compare their spatial distribution. The ionic lines show a clumpy distribution of material around the main cavity of NGC 40, with the emission from [Ar II] being the most extended, whilst the PAHs show a rather smooth spatial distribution. Analysis of ratio maps shows the presence of a toroidal structur…
The large-scale distribution of globular clusters in the central region of the Coma cluster of galaxies is derived through the analysis of Hubble Space Telescope/Advanced Camera for Surveys data. Data from three different HST observing programs are combined in order to obtain a full surface density map of globular clusters in the core of Coma. A total of 22,426 Globular cluster candidates were selected through a detailed morphological inspection and the analysis of their magnitude and colors in two wavebands, F475W (Sloan g) and F814W (I). The spatial distribution of globular clusters defines …
We used the Submillimeter Array (SMA) to observe the thermal polarized dust emission from the protostellar source NGC 2024 FIR 5. The polarized emission outlines a partial hourglass morphology for the plane-of-sky component of the core magnetic field. Our data are consistent with previous BIMA maps, and the overall magnetic field geometries obtained with both instruments are similar. We resolve the main core into two components, FIR 5A and FIR 5B. A possible explanation for the asymmetrical field lies in depolarization effects due to the lack of internal heating from FIR 5B source, which may b…
