Context.
The final stages of molecular cloud evolution involve cloud disruption due to feedback by massive stars, with recent literature suggesting the importance of early (i.e., pre-supernova) ...feedback mechanisms.
Aims.
We aim to determine whether feedback from massive stars in H
II
regions has a measurable impact on the physical properties of molecular clouds at a characteristic scale of ~ 100 pc, and whether the imprint of feedback on the molecular gas depends on the local galactic environment.
Methods.
We identified giant molecular clouds (GMCs) associated with H
II
regions for a sample of 19 nearby galaxies from catalogs of GMCs and H
II
regions released by the PHANGS-ALMA and PHANGS-MUSE surveys, using the overlap of the CO and H
α
emission as the key criterion for physical association. We compared the distributions of GMC and H
II
region properties for paired and non-paired objects. We investigated correlations between GMC and H
II
region properties among galaxies and across different galactic environments to determine whether GMCs that are associated with H
II
regions have significantly distinct physical properties compared to the parent GMC population.
Results.
We identify trends between the H
α
luminosity of an H
II
region and the CO peak brightness and molecular mass of GMCs that we tentatively attribute to a direct physical connection between the matched objects, and which arise independently of the underlying environmental variations of GMC and H
II
region properties within galaxies. The study of the full sample nevertheless hides a large galaxy-to-galaxy variability.
Conclusions.
At the ~100 pc scales accessed by the PHANGS-ALMA and PHANGS-MUSE data, pre-supernova feedback mechanisms in H
II
regions have a subtle but measurable impact on the properties of the surrounding molecular gas, as inferred from CO observations.
We present a comprehensive study of the massive binary system HM1~8, based on
multi-epoch high resolution spectroscopy, $V$-band photometry and archival
X-ray data. Spectra from the OWN Survey, a ...high resolution optical monitoring
of Southern O and WN stars, are used to analyse the spectral morphology and
perform quantitative spectroscopic analysis of both stellar components. The
primary and secondary components are classified as O4.5~IV(f) and O9.7~V,
respectively. From a radial-velocity (RV) study we derived a set of orbital
parameters for the system. We found an eccentric orbit ($e=0.14 \pm 0.01$) with
a period of $P = 5.87820 \pm 0.00008$~days. Through the simultaneous analysis
of the RVs and the $V$-band light curve we derived an orbital inclination of
$70.0^{\circ} \pm 2.0$ and stellar masses of
$M_a=33.6^{+1.4}_{-1.2}~\text{M}_{\sun}$ for the primary, and
$M_b=17.7^{+0.5}_{-0.7}~\text{M}_{\sun}$ for the secondary. The components show
projected rotational velocities $v_1\sin{i}=105 \pm 14~\text{km~s}^{-1}$ and
$v_2\sin{i}=82 \pm 15~\text{km~s}^{-1}$, respectively. A tidal evolution
analysis is also performed and found to be in agreement with the orbital
characteristics. Finally, the available X-ray observations show no evidence of
a colliding winds region, therefore the X-ray emission is attributed to stellar
winds.
We identify giant molecular clouds (GMCs) associated with HII regions for a sample of 19 nearby galaxies using catalogs of GMCs and H regions released by the PHANGS-ALMA and PHANGS-MUSE surveys, ...using the overlap of the CO and H{\alpha} emission as the key criterion for physical association. We compare the distributions of GMC and HII region properties for paired and non-paired objects. We investigate correlations between GMC and HII region properties among galaxies and across different galactic environments to determine whether GMCs that are associated with HII regions have significantly distinct physical properties to the parent GMC population. We identify trends between the H{\alpha} luminosity of an HII region and the CO peak brightness and the molecular mass of GMCs that we tentatively attribute to a direct physical connection between the matched objects, and which arise independently of underlying environmental variations of GMC and HII region properties within galaxies. The study of the full sample nevertheless hides a large variability galaxy by galaxy. Our results suggests that at the ~100 pc scales accessed by the PHANGS-ALMA and PHANGS-MUSE data, pre-supernova feedback mechanisms in HII regions have a subtle but measurable impact on the properties of the surrounding molecular gas, as inferred from CO observations.
We present PHANGS-ALMA, the first survey to map CO J=2-1 line emission at ~1" ~ 100pc spatial resolution from a representative sample of 90 nearby (d<~20 Mpc) galaxies that lie on or near the z=0 ..."main sequence" of star-forming galaxies. CO line emission traces the bulk distribution of molecular gas, which is the cold, star-forming phase of the interstellar medium. At the resolution achieved by PHANGS-ALMA, each beam reaches the size of a typical individual giant molecular cloud (GMC), so that these data can be used to measure the demographics, life-cycle, and physical state of molecular clouds across the population of galaxies where the majority of stars form at z=0. This paper describes the scientific motivation and background for the survey, sample selection, global properties of the targets, ALMA observations, and characteristics of the delivered ALMA data and derived data products. As the ALMA sample serves as the parent sample for parallel surveys with VLT/MUSE, HST, AstroSat, VLA, and other facilities, we include a detailed discussion of the sample selection. We detail the estimation of galaxy mass, size, star formation rate, CO luminosity, and other properties, compare estimates using different systems and provide best-estimate integrated measurements for each target. We also report the design and execution of the ALMA observations, which combine a Cycle~5 Large Program, a series of smaller programs, and archival observations. Finally, we present the first 1" resolution atlas of CO emission from nearby galaxies and describe the properties and contents of the first PHANGS-ALMA public data release.
We describe the processing of the PHANGS-ALMA survey and present the PHANGS-ALMA pipeline, a public software package that processes calibrated interferometric and total power data into science-ready ...data products. PHANGS-ALMA is a large, high-resolution survey of CO J=2-1 emission from nearby galaxies. The observations combine ALMA's main 12-m array, the 7-m array, and total power observations and use mosaics of dozens to hundreds of individual pointings. We describe the processing of the u-v data, imaging and deconvolution, linear mosaicking, combining interferometer and total power data, noise estimation, masking, data product creation, and quality assurance. Our pipeline has a general design and can also be applied to VLA and ALMA observations of other spectral lines and continuum emission. We highlight our recipe for deconvolution of complex spectral line observations, which combines multiscale clean, single scale clean, and automatic mask generation in a way that appears robust and effective. We also emphasize our two-track approach to masking and data product creation. We construct one set of "broadly masked" data products, which have high completeness but significant contamination by noise, and another set of "strictly masked" data products, which have high confidence but exclude faint, low signal-to-noise emission. Our quality assurance tests, supported by simulations, demonstrate that 12-m+7-m deconvolved data recover a total flux that is significantly closer to the total power flux than the 7-m deconvolved data alone. In the appendices, we measure the stability of the ALMA total power calibration in PHANGS--ALMA and test the performance of popular short-spacing correction algorithms.
Potato (
L.) is mainly characterized by its antioxidant and healing properties. Therefore, this study aimed to evaluate the effects of an ointment based on
L. "papa tumbay" on burns induced in Balb/c ...mice (
).
The experimental animals were divided into four groups (n = 5/group) 48 h before second-degree burns were inducted. After epilating the loin areas of the mice and anesthetizing them with ketamine/xylazine (80 mg/kg/10 mg/kg) through intraperitoneal (i.p.) route, a round metal rod (0.7 cm in diameter) was placed on the depilated skin at a temperature of 100°C for 5 s. Group I was not given any treatment, Group II was treated with silver sulfadiazine (1%), and the other two groups (III and IV) were treated with the ointment formulated based on
L. "papa tumbay" at 1% and 2%, respectively. After performing the treatment for 21 days, the mice were euthanized using i.p. sodium pentobarbital (185 mg/kg) to obtain skin samples. The samples were preserved in 10% neutral-buffered formalin and subjected to histopathological analysis.
We found statistically significant differences in the histopathological sections between the groups (p < 0.05). The abundant collagen and fibroblasts observed in the direction of the dermis in Groups III and IV indicate that the phytoconstituents present in the potato might promote the healing of the second-degree burns until day 21 of treatment.
Our findings showed that the ointments based on the ethanolic extracts of
L. "papa tumbay," especially the 2% ointment, might accelerate the healing of second-degree burns induced in Balb/c mice.
