J. Vásquez

Universidad Pontificia Bolivariana

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C. E. Cappa

Universidad Nacional de La Plata

M. Rubio

University of Chile

N. U. Duronea

Instituto de Astrofísica de La Plata

V. Firpo

Gemini South Observatory

G. A. Romero

Universidad Nacional de La Plata

S. Cichowolski

Institute of Astronomy and Space Physics

C. E. Cappa

Consejo Nacional de Investigaciones Científicas y Técnicas

E. M. Arnal

Universidad Nacional de La Plata

M. M. Vazzano

Instituto Argentino de Radioastronomía

S. Pineault

Université Laval

Cooperative Institutions

University of Concepción

Consejo Nacional de Investigaciones Científicas y Técnicas

Universidad Nacional de La Plata

Instituto Argentino de Radioastronomía

University of Chile

Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro

Universidad Nacional Autónoma de México

University of Padua

Centro Científico Tecnológico - San Juan

Istituto Nazionale di Fisica Nucleare, Sezione di Pavia

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Molecular gas and star formation toward the IR dust bubble S 24 and its environs

Astronomy and Astrophysics (2015)

C. E. Cappa N. U. Duronea V. Firpo J. Vásquez C. H. López-Caraballo

We present a multi-wavelength analysis of the infrared dust bubble S24, and its environs, with the aim of investigating the characteristics of the molecular gas and the interstellar dust linked to them, and analyzing the evolutionary status of the young stellar objects (YSOs) identified there. Using APEX data, we mapped the molecular emission in the CO(2-1), $^{13}$CO(2-1), C$^{18}$O(2-1), and $^{13}$CO(3-2) lines in a region of about 5'x 5' in size around the bubble. The cold dust distribution was analyzed using ATLASGAL and Herschel images. Complementary IR and radio data were also used.The molecular gas linked to the S24 bubble, G341.220-0.213, and G341.217-0.237 has velocities between -48.0 km sec$^{-1}$ and -40.0 km sec$^{-1}$. The gas distribution reveals a shell-like molecular structure of $\sim$0.8 pc in radius bordering the bubble. A cold dust counterpart of the shell is detected in the LABOCA and Herschel images.The presence of extended emission at 24 $\mu$m and radio continuum emission inside the bubble indicates that the bubble is a compact HII region. Part of the molecular gas bordering S24 coincides with the extended infrared dust cloud SDC341.194-0.221. A cold molecular clump is present at the interface between S24 and G341.217-0.237. As regards G341.220-0.213, the presence of an arc-like molecular structure at the northern and eastern sections of this IR source indicates that G341.220-0.213 is interacting with the molecular gas. Several YSO candidates are found to be linked to the IR extended sources, thus confirming their nature as active star-forming regions. The total gas mass in the region and the H$_2$ ambient density amount to 10300 M$_{\odot}$ and 5900 cm$^{-3}$, indicating that G341.220-0.213, G341.217-0.237, and the S24 HII region are evolving in a high density medium. A triggering star formation scenario is also investigated.

Young stellar object

10.1051/0004-6361/201525949

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THE ISM AROUND WR 152 AND WR 153AB

Revista Mexicana de Astronomía y Astrofísica (2008)

C. E. Cappa J. Vásquez E. M. Arnal S. Cichowolski S. Pineault

We analyzed the distribution of the interstellar matter in the environs of the WR stars WR 152 and WR 153ab, associated with ring nebulae in the Sh2-132 Hii region. Our study is based on radio data (continuum, Hi, and CO(1-0) observations) and images in the far and mid IR. We have detected the radio continuum and far IR counterparts of the ionized shells related to WR 152, as well as Hi gas linked to the outer ionized shell. The distributions of the ionized and molecular gas related to WR 153ab and that of the PAHs suggest the presence of photodissociation regions at the interface between the ionized and molecular material. We estimate the main physical parameters of the gas components.

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The Role of Estrogens in Mastopathy and Mammary Cancer in Perimenopausal Women

Journal of the American Geriatrics Society (1982)

Robert B. Greenblatt J. Vásquez Constantine Samaras C. Nezhat

Fibrocystic disease of the breast (FCD) is an exaggeration of the normal physiologic response to cyclic estrogen and progesterone stimulation. The disorder can persist, with much less severity, in the menopausal woman. Whether FCD predisposes to mammary cancer remains moot. A new steroidal agent, danazol, can eliminate nodosities in the majority of women with FCD. Thermography may identify women who are at greater risk because of increased heat production. Mammography should be employed in women with persistently abnormal thermograms, even though no suggestive breast masses are palpable. Needle biopsy or surgical biopsy should be undertaken whenever a firm indurated mass is palpated, regardless of negative findings with a thermogram or mammogram. In a series of 1548 women treated for 10,715 women‐years, the incidence of breast cancer after prolonged estrogen therapy was not increased. Although estrogens and prolactin have been incriminated in the etiology of mammary cancer, no hard facts exist to confirm such allegations.

Etiology

10.1111/j.1532-5415.1982.tb01298.x

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Multifrequency study of the ring nebula SG 13

Monthly Notices of the Royal Astronomical Society (2009)

J. Vásquez C. E. Cappa S. Pineault

We investigate the morphology and kinematics of the interstellar medium in the environs of the open cluster Mrk 50, which includes the Wolf–Rayet star WR 157 and a number of early B-type stars. The analysis was performed using radio continuum images at 408 and 1420 MHz, and H i 21-cm line data taken from the Canadian Galactic Plane Survey, molecular observations of the 12CO (J= 1 → 0) line at 115 GHz from the Five College Radio Astronomy Observatory and available mid- and far-infrared (FIR) observations obtained with the Midcourse Space Experiment and IRAS satellites, respectively. This study allowed the identification of the radio continuum and molecular counterpart of the ring nebula SG 13, while no neutral atomic structure was found to be associated. The nebula is also detected in the images in the mid- and FIR, showing the existence of dust well mixed with the ionized gas. We estimate the main physical parameters of the material linked to the nebula. The interstellar gas distribution in the environs of Mrk 50 is compatible with a stellar wind bubble created by the mass loss from WR 157. The distribution of young stellar object candidates in the region shows that the stellar formation activity may be present in the molecular shell that encircles the ring nebula.

Galactic plane

H II region

Wolf–Rayet star

Dark nebula

10.1111/j.1365-2966.2008.14188.x

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Ionized gas, molecules and dust in Sh2-132

Monthly Notices of the Royal Astronomical Society (2010)

J. Vásquez C. E. Cappa S. Pineault N. U. Duronea

We analyze the various interstellar components of the HII region Sh2-132. The main stellar source is the double binary system that includes the Wolf-Rayet star WR153ab. We use radio continuum images at 408 and 1420 MHz, and HI 21cm line data taken from the Canadian Galactic Plane Survey, molecular observations of the 12CO(1-0) line at 115 GHz from the Five College Radio Astronomy Observatory, and available mid and far IR observations obtained with the MSX and IRAS satellites, respectively. Sh2-132 is composed of two shells showing radio continuum counterparts at both frequencies. The emission is thermal in nature. The estimated rms electron density and ionized mass of the nebula are n_e = 20 cm^{-3} and M_HII = 1500 Mo. The distribution of the CO emission shows molecular gas bordering the ionized nebula and interacting with it. The velocities of the molecular gas is in the range --38 to --53 km/s, similar to the velocity of the ionized gas. The emission at 8.3 mic. reveals a ring like feature of about 15' that encircles the bright optical regions. This emission is due to the PAHs and marks the location of photodissociation regions. The gas distribution in the environs of Sh2-132 can be explained in a scenario where the massive stars in the region photodissociated, ionized, and swept-up the dense molecular material from the parental cloud through their strong stellar winds and intense UV photon flux.

Orion Nebula

H II region

10.1111/j.1365-2966.2010.16590.x

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A multifrequency study of the active star forming region NGC 6357

Proceedings of the International Astronomical Union (2006)

C. E. Cappa R. H. Barbá Michelle Arnal N. U. Duronea E. Fernández Lajús

To investigate the interaction of the massive stars with the gas and dust in the active star forming region NGC 6357, located in the Sagittarius spiral arm at a distance of 1.7-2.6 kpc (Massey et al . 2001), we analyzed the distribution of the neutral and ionized gas, and that of the dust, based on Hα, [O III ] and [S II ] images obtained with the Curtis-Schmidt telescope at CTIO, radio continuum observations at 1.465 MHz obtained with the Very Large Array (NRAO) in the DnC configuration (synthesized beam = 38″), Hi data from the Parkes survey (angular resolution = 15′), CO(1-0) observations obtained with the Nanten radiotelescope at Las Campanas Observatory (angular resolution = 2.7′), and IR images in the four MSX bands (angular resolution = 18.3″).

Angular diameter

10.1017/s1743921307001883

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A multifrequency study of the active star-forming complex NGC 6357 - I. Interstellar structures linked to the open cluster Pis 24

Monthly Notices of the Royal Astronomical Society (2011)

C. E. Cappa R. H. Barbá N. U. Duronea J. Vásquez E. M. Arnal

We investigate the distribution of the gas (ionized, neutral atomic and molecular), and interstellar dust in the complex star forming region NGC6357 with the goal of studying the interplay between the massive stars in the open cluster Pis24 and the surrounding interstellar matter. Our study of the distribution of the ionized gas is based on narrow-band Hhalfa, [SII], and [OIII] images obtained with the Curtis-Schmidt Camera at CTIO, Chile, and on radio continuum observations at 1465 MHz taken with the VLA with a synthesized beam of 40 arcsec. The distribution of the molecular gas is analyzed using 12CO(1-0) data obtained with the Nanten radiotelescope, Chile (angular resolution = 2.7 arcmin). The interstellar dust distribution was studied using mid-infrared data from the GLIMPSE survey and far-infrared observations from IRAS. NGC6357 consists of a large ionized shell and a number of smaller optical nebulosities. The optical, radio continuum, and near- and mid-IR images delineate the distributions of the ionized gas and interstellar dust in the HII regions and in previously unknown wind blown bubbles linked to the massive stars in Pis24 revealing surrounding photodissociation regions. The CO line observations allowed us to identify the molecular counterparts of the ionized structures in the complex and to confirm the presence of photodissociation regions. The action of the WR star HD157504 on the surrounding gas was also investigated. The molecular mass in the complex is estimated to be (4+/-2)X10^5 Mo. Mean electron densities derived from the radio data suggest electron densities > 200 cm^-3, indicating that NGC6357 is a complex formed in a region of high ambient density. The known massive stars in Pis24 and a number of newly inferred massive stars are mainly responsible for the excitation and photodissociation of the parental molecular cloud.

10.1111/j.1365-2966.2011.18902.x

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Molecular gas associated with IRAS 10361-5830

Astronomy and Astrophysics (2014)

M. M. Vazzano C. E. Cappa J. Vásquez M. Rubio G. A. Romero

Aims. We analyze the distribution of the molecular gas and dust in the molecular clump linked to IRAS 10361-5830, located in the environs of the bubble-shaped Hii region Gum 31 in the Carina region, with the aim of determining the main parameters of the associated material and of investigating the evolutionary state of the young stellar objects identified there.

10.1051/0004-6361/201423369

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IR dust bubbles: gas, dust and star formation in the S21-S24 complex

E. C. Cappa A. G. Romero J. Vásquez V. Firpo N. Dorunea

Circumstellar dust

Mineral dust

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Star formation activity around Sh2-165 and Sh2-166

Boletin de la Asociacion Argentina de Astronomia La Plata Argentina (2011)

S. Cichowolski M. E. Ortega J. Vásquez Gustavo E. Romero C. E. Cappa

1) INTRODUCTION Massive stars have a huge impact on their surrounding interstellar medium as they emit a large number of ionizing photons, creating HII regions around them. The evolution of these regions strongly affects the structure and dynamics of the surrounding gas, and may induce the formation of new stars. In this work we analyze two HII regions: Sh2-165 and Sh2-166, with the purpose of exploring the possible presence of star formation activity in their environs. To carry out this study, a multiwavelength analysis is essential. The data were obtained from public surveys: the Canadian Galactic Plane Survey (CGPS), the Five College Radio Astronomical Observatory (FCRAO) CO Survey, the MSX Galactic Plane Survey and the Digitized Sky Survey (DSS).

Galactic plane

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