The Millimetre Astronomy Legacy Team 90GHz survey aims to characterise the physical and chemical evolution of high-mass clumps. Recently completed, it mapped 90GHz line emission towards 3246 high-mass clumps identified from the ATLASGAL 870um Galactic plane survey. By utilising the broad frequency coverage of the Mopra telescope's spectrometer, maps in 16 different emission lines were simultaneously obtained. Here, we describe the first catalogue of the detected line emission, generated by Gaussian profile fitting to spectra extracted towards each clumps' 870um dust continuum peak. Synthetic spectra show that the catalogue has a completeness of >95%, a probability of a false-positive detection of <0.3%, and a relative uncertainty in the measured quantities of <20% over the range of detection criteria. The detection rates are highest for the (1-0) transitions of HCO^+^, HNC, N_2_H^+^, and HCN (~77-89%). Almost all clumps (~95%) are detected in at least one of the molecular transitions, just over half of the clumps (~53%) are detected in four or more of the transitions, while only one clump is detected in 13 transitions. We find several striking trends in the ensemble of properties for the different molecular transitions when plotted as a function of the clumps' evolutionary state as estimated from Spitzer mid-IR images, including (1) HNC is relatively brighter in colder, less evolved clumps than those that show active star formation, (2) N2H+ is relatively brighter in the earlier stages, (3) that the observed optical depth decreases as the clumps evolve, and (4) the optically thickest HCO^+^ emission shows a 'blue-red asymmetry' indicating overall collapse that monotonically decreases as the clumps evolve. This catalogue represents the largest compiled database of line emission towards high-mass clumps and is a valuable data set for detailed studies of these objects.
Hydrocarbons are ubiquitous in the interstellar medium, but their formation is still not well understood, depending on the physical environment they are found in. Messier 8 (M8) is host to one of the brightest Hii regions and photodissociation regions (PDRs) in our galaxy. With the observed C_2_H and c-C_3_H_2_ data toward M8, we aim at obtaining their densities and abundances and to shed some light on their formation mechanism. Using the Atacama Pathfinder Experiment (APEX) 12m, and the Institut de Radioastronomie Millimetrique (IRAM) 30m telescopes, we performed a line survey toward Herschel 36 (Her 36), which is the main ionizing stellar system in M8, and an imaging survey within 1.3x1.3pc around Her 36 of various transitions of C_2_H and C_3_H_2_. We used both Local Thermodynamic Equilibrium (LTE) and non-LTE methods to determine the physical conditions of the emitting gas along with the column densities and abundances of the observed species, which we compared with (updated) gas phase photochemical PDR models. In order to examine the role of polycyclic aromatic hydrocarbons (PAHs) in the formation of small hydrocarbons and to investigate their association with the Hii region, the PDR and the molecular cloud, we compared archival Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) 8{mu}m and the Spectral and Photometric Imaging Receiver (SPIRE) 250{mu}m continuum images with the C_2_H emission maps. We observed a total of three rotational transitions of C_2_H with their hyperfine structure components and four rotational transitions of C_3_H_2_ with ortho and para symmetries toward the HII region and the PDR of M8. Fragmentation of PAHs seems less likely to contribute to the formation of small hydrocarbons as the 8 m emission does not follow the distribution of C_2_H emission, which is more associated with the molecular cloud toward the north-west of Her 36. From the quantitative analysis, we obtained abundances of 10^-8 ^and 10^-9^ for C_2_H and c-C_3_H_2_ respectively, and volume densities of the hydrocarbon emitting gas in the range n(H_2_)~5x10^4^-5x10^6^cm^-3^. The observed column densities of C_2_H and c-C_3_H_2_ are reproduced reasonably well by our PDR models. This supports the idea that in high-UV flux PDRs, gas phase chemistry is sufficient to explain hydrocarbon abundances.
Manganese abundances are sensitive probes of the progenitors of TypeIa supernovae (SNe Ia). In this work, we present a catalog of manganese abundances in dwarf spheroidal satellites of the Milky Way, measured using medium-resolution spectroscopy. Using a simple chemical evolution model, we infer the manganese yield of SNe Ia in the Sculptor dwarf spheroidal galaxy (dSph) and compare to theoretical yields. The sub-solar yield from SNIa ([Mn/Fe]_Ia_=-0.30_-0.03_^+0.03^ at [Fe/H]=-1.5dex, with negligible dependence on metallicity) implies that sub-Chandrasekhar-mass (sub-MCh) white dwarf progenitors are the dominant channel of SNe Ia at early times in this galaxy, although some fraction (>~20%) of M_Ch_ Type Ia or Type Iax SNe are still needed to produce the observed yield. First-order corrections for deviations from local thermodynamic equilibrium increase the inferred [Mn/Fe]_Ia_ by as much as ~0.3dex. However, our results also suggest that the nucleosynthetic source of SNe Ia may depend on environment. In particular, we find that dSphs with extended star formation histories (Leo I, Fornax dSphs) appear to have higher [Mn/Fe] at a given metallicity than galaxies with early bursts of star formation (Sculptor dSph), suggesting that M_Ch_ progenitors may become the dominant channel of SNe Ia at later times in a galaxy's chemical evolution.
The search for new global scaling relations linking the physical properties of galaxies has a fundamental interest. Furthermore, their recovery from spatially resolved relations has been in the spotlight of integral field spectroscopy (IFS). In this study, we investigate the existence of global and local relations between stellar age (Age*) and gas-phase metallicity (Zg). To this aim, we analyze IFS data for a sample of 736 star-forming disk galaxies from the MaNGA survey. We report a positive correlation between the global Zg and D(4000) (an indicator of stellar age), with a slope that decreases with increasing galaxy mass. Locally, a similar trend is found when analyzing the Zg and D(4000) of the star-forming regions, as well as the residuals resulting from removing the radial gradients of both parameters. The local laws have systematically smaller slopes than the global one. We ascribe this difference to random errors that cause the true slope of the Age*-Zg relation to be systematically underestimated when performing a least-squares fitting. The explored relation is intimately linked with the already known relation between gas metallicity and star formation rate at fixed mass, both presenting a common physical origin.
We have conducted a mapping spectral line survey toward the Galactic giant molecular cloud W51 in the 3mm band with the Mopra 22m telescope in order to study an averaged chemical composition of the gas extended over a molecular-cloud scale in our Galaxy. We have observed the area of 25'x30', which corresponds to 39pcx47pc. The frequency ranges of the observation are 85.1-101.1GHz and 107.0-114.9GHz. In the spectrum spatially averaged over the observed area, spectral lines of 12 molecular species and 4 additional isotopologues are identified. An intensity pattern of the spatially averaged spectrum is found to be similar to that of the spiral arm in the external galaxy M51, indicating that these two sources have similar chemical compositions. The observed area has been classified into five subregions according to the integrated intensity of ^13^CO(J=1-0) (I_13CO_), and contributions of the fluxes of 11 molecular lines from each subregion to the averaged spectrum have been evaluated. For most of the molecular species, 50% or more of the flux comes from the subregions with I_13CO_ from 25 to 100K.km.s^-1^, which does not involve active star-forming regions. Therefore, the molecular-cloud-scale spectrum observed in the 3mm band hardly represents the chemical composition of star-forming cores, but mainly represents the chemical composition of an extended quiescent molecular gas. The present result constitutes a sound base for interpreting the spectra of external galaxies at a resolution of a molecular-cloud scale (~10pc) or larger.
We analyse in detail the rich emission line spectrum of Mark 110 to determine the physical conditions in the nucleus of this object, a peculiar NLS1 without any detectable Fe II emission associated with the broad line region and with a {lambda}5007/H{beta} line ratio unusually large for a NLS1. We use 24 spectra obtained with the Marcario Low Resolution Spectrograph attached at the prime focus of the 9.2m Hobby-Eberly telescope at the McDonald observatory. We fitted the spectrum by identifying all the emission lines (about 220) detected in the wavelength range 4200-6900{AA} (at rest).
In this paper we present MASCARA-2 b, a hot Jupiter transiting the m_V_=7.6 A2 star HD 185603. Since early 2015, MASCARA has taken more than 1.6 million flux measurements of the star, corresponding to a total of almost 3000 hours of observations, revealing a periodic dimming in the flux with a depth of 1.3%. Photometric follow-up observations were performed with the NITES and IAC80 telescopes and spectroscopic measurements were obtained with the Hertzsprung SONG telescope. We find MASCARA-2 b orbits HD 185603 with a period of 3.474119^+0.000005^_-0.000006_ days at a distance of 0.057+/-0.006AU, has a radius of 1.83+/-0.07R_J_ and place a 99 % upper limit on the mass of <17M_J_. HD 185603 is a rapidly rotating early-type star with an effective temperature of 8980^+90^_-130_K and a mass and radius of 1.89^+0.06^_-0.05_M_sun_, 1.60+/-0.06R_sun_, respectively. Contrary to most other hot Jupiters transiting early-type stars, the projected planet orbital axis and stellar spin axis are found to be aligned with {lambda}=0.6+/-4{deg}. The brightness of the host star and the high equilibrium temperature, 2260+/-50K, of MASCARA-2 b make it a suitable target for atmospheric studies from the ground and space. Of particular interest is the detection of TiO, which has recently been detected in the similarly hot planets WASP-33 b and WASP-19 b.
We report the discovery of MASCARA-1 b, the first exoplanet discovered with the Multi-site All-Sky CAmeRA (MASCARA). It is a hot Jupiter orbiting a bright m_V_=8.3, rapidly rotating (vsini>100km/s) A8 star with a period of 2.148780+/-0.000008 days. The planet has a mass and radius of 3.7+/-0.9M_J_ and 1.5+/-0.3R_J_, respectively. As with most hot Jupiters transiting early-type stars we find a misalignment between the planet orbital axis and the stellar spin axis, which may be signature of the formation and migration histories of this family of planets. MASCARA-1 b has a mean density of 1.5+/-0.9g/cm^3^ and an equilibrium temperature of 2570^+50^_-30_K, one of the highest temperatures known for a hot Jupiter to date. The system is reminiscent of WASP-33, but the host star lacks apparent delta-scuti variations, making the planet an ideal target for atmospheric characterization. We expect this to be the first of a series of hot Jupiters transiting bright early-type stars that will be discovered by MASCARA.
We used the HARPS-North high resolution spectrograph (R=115000) at Telescopio Nazionale Galileo (TNG) to observe one transit of the highly irradiated planet MASCARA-2b/KELT-20b. Using only one transit observation, we are able to clearly resolve the spectral features of the atomic sodium (NaI) doublet and the H{alpha} line in its atmosphere, which are corroborated with the transmission calculated from their respective transmission light curves (TLC). In particular, we resolve two spectral features centred on the NaI doublet position with an averaged absorption depth of 0.17+/-0.03% for a 0.75{AA} bandwidth with line contrasts of 0.44+/-0.11% (D2) and 0.37+/-0.08% (D1). The NaI TLC have also been computed, showing a large Rossiter-McLaughlin (RM) effect, which has a 0.20+/-0.05% NaI transit absorption for a 0.75{AA} passband that is consistent with the absorption depth value measured from the final transmission spectrum. We observe a second feature centred on the H{alpha} line with 0.6+/-0.1% contrast and an absorption depth of 0.59+/-0.08% for a 0.75{AA} passband that has consistent absorptions in its TLC, which corresponds to an effective radius of R'/Rp=1.20+/-0.04. While the signal-to-noise ratio (S/N) of the final transmission spectrum is not sufficient to adjust different temperature profiles to the lines, we find that higher temperatures than the equilibrium (Teq=2260+/-50K) are needed to explain the lines contrast. Particularly, we find that the NaI lines core require a temperature of T=4210+/-180K and that H{alpha} requires a temperature of T=4330+/-520K. MASCARA-2b, like other planets orbiting A-type stars, receives a large amount of UV energy from its host star. This energy excites the atomic hydrogen and produces H{alpha} absorption, leading to the expansion and abrasion of the atmosphere. The study of other Balmer lines in the transmission spectrum would allow the determination of the atmospheric temperature profile and the calculation of the lifetime of the atmosphere with escape rate measurements. In the case of MASCARA-2b, residual features are observed in the H{beta} and H{gamma} lines, but they are not statistically significant.More transit observations are needed to confirm our findings in NaI and H{alpha} and to build up enough S/N to explore the presence of H{beta} and H{gamma} planetary absorptions.
Ultra-hot Jupiters orbit very close to their host star and consequently receive strong irradiation, causing their atmospheric chemistry to be different from the common gas giants. Here, we have studied the atmosphere of one of these particular hot planets, MASCARA- 2b/KELT-20b, using four transit observations with high resolution spectroscopy facilities. Three of these observations were performed with HARPS-N and one with CARMENES. Additionally, we simultaneously observed one of the transits with MuSCAT2 to monitor possible spots in the stellar surface. At high resolution, the transmission residuals show the effects of Rossiter-McLaughlin and centre- to-limb variations from the stellar lines profiles, which we have corrected to finally extract the transmission spectra of the planet. We clearly observe the absorption features of CaII, FeII, NaI, H{alpha}, and H{beta} in the atmosphere of MASCARA-2b, and indications of H{gamma} and MgI at low signal-to-noise ratio. In the case of NaI, the true absorption is difficult to disentangle from the strong telluric and interstellar contamination. The results obtained with CARMENES and HARPS-N are consistent, measuring an H{alpha} absorption depth of 0.68+/-0.05 and 0.59+/-0.07%, and NaI absorption of 0.11+/-0.04 and 0.09+/-0.05% for a 0.75{AA} passband, in the two instruments respectively. The H{alpha} absorption corresponds to ~1.2Rp, which implies an expanded atmosphere, as a result of the gas heating caused by the irradiation received from the host star. For H{beta} and H{gamma} only HARPS-N covers this wavelength range, measuring an absorption depth of 0.28+/-0.06 and 0.21+/-0.07%, respectively. For CaII, only CARMENES covers this wavelength range measuring an absorption depth of 0.28+/-0.05, 0.41+/-0.05 and 0.27+/-0.06% for CaII {lambda}8498{AA}, {lambda}8542{AA} and {lambda}8662{AA} lines, respectively. Three additional absorption lines of FeII are observed in the transmission spectrum by HARPS-N (partially covered by CARMENES), measuring an average absorption depth of 0.08+/-0.04% (0.75{AA} passband). The results presented here are consistent with theoretical models of ultra-hot Jupiters atmospheres, suggesting the emergence of an ionised gas on the day-side of such planets. Calcium and iron, together with other elements, are expected to be singly ionised at these temperatures and be more numerous than its neutral state. The Calcium triplet lines are detected here for the first time in transmission in an exoplanet atmosphere. Description: The transmission spectra and of MASCARA-2b/KELT-20b are presented. Three transits with HARPS-North at TNG telescope were retrieved and one transit with CARMENES at 3.5 telescope at CAHA Observatory. For each spectral line the transmission spectra of MASCARA-2b/KELT-20b after correcting the CLV + RME are presented here. We note that in some cases the transmission spectrum of a specific line also includes transmission lines located close to the main spectral line (e.g. in case of NaI doublet). However, it is important to note that only the main spectral line of each file (see files name) includes the CLV+RME corrections. You need to work with specific files.
