D. May
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Previous Organizations / Institutes
The organizations / institutes from the scholar's other articles in the past ten years
Research Subjects
Research Interests
D. May has a total of 6 co-authors. Here are the top co-authors by number of shared publications:
I. S. Andrade
Institute of Astronomy, Geophysics and Atmospheric Sciences, University of São Paulo Rua do Matão 1226, Cidade Universitária, São Paulo, SP CEP 05508-090, Brazil
2 shared publications- J. E. Steiner
Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, 05508-900 São Paulo, Brazil
2 shared publications - Tiago V. Ricci
Universidade Federal da Fronteira Sul
2 shared publications J. E. Steiner
Instituto de Astronomia Geofísica e Ciências Atmosféricas, Universidade de São Paulo Rua do Matão 1226, Cidade Universitária, São Paulo, SP CEP 05508-090, Brazil
1 shared publicationR. B. Menezes
Instituto de Astronomia Geofísica e Ciências Atmosféricas, Universidade de São Paulo Rua do Matão 1226, Cidade Universitária, São Paulo, SP CEP 05508-090, Brazil
1 shared publication- R. B. Menezes
Instituto de Astronomia Geofísica e Ciências Atmosféricas Universidade de São Paulo Rua do Matão 1226 Cidade Universitária 05508-090 São Paulo SP CEP Brazil
1 shared publication
Latest Publications
- Open Access
- 11 April 2017
- Published by Oxford University Press (OUP) in Monthly Notices of the Royal Astronomical Society
- Vol. 469 (1) , 994-1025
A two-stage outflow in NGC 1068
We present an analysis of the Seyfert 2 galaxy NGC 1068 of archive data from the Spectrograph for INtegral Field Observations in the Near Infrared (SINFONI)-Very Large Telescope, in the HK bands with pixel scales of 0.1 (data set 1 – DS1) and 0.025 (DS2) arcsec. The data are revisited with a sophisticated data treatment, such as the differential atmospheric refraction correction and the application of a Butterworth filtering and deconvolution. The gain in the process is quantified by a significant improvement in the Strehl ratio and it shows that an unprecedented high spatial resolution is achieved. For DS1, a detailed study of the H2, [Fe ii] and [Si vi] emission lines reveals a three-phase gas morphology: (1) the low-velocity [Fe ii] emission representing the glowing wall of an hourglass structure, (2) the high-velocity compact blobs of low and high ionization emissions filling the hourglass volume and (3) the distribution of H2 molecular gas defines the thick and irregular walls of a bubble surrounding a cavity. Both the hourglass and the molecular emissions have an asymmetry caused by the fragmentation of the north-eastern molecular wall, closest to the active galactic nucleus, resulting in high-velocity compact blobs of ionized gas outside the bubble. The south-western part of the bubble is excavated by the jet, where the blobs remain confined and are blown along the bubble's inner boundary. We propose that those blobs are driven by a hot ‘secondary wind’ coming from the spot where the jet interacts and injects its energy in the molecular gas. The combination of a primary wind launched by the central source and the secondary wind is what we call a two-stage outflow. For DS2, we detected a [Si vi] outflow nearly coplanar to the maser disc and orthogonal to the CO outflow found by a previous study. Such unexpected scenario is interpreted as the interaction between the central radiation field and a two-phase gas density torus.
- 11 April 2017
- Published by Oxford University Press (OUP) in Monthly Notices of the Royal Astronomical Society
- Vol. 469 (1) , 994-1025
Open AccessA two-stage outflow in NGC 1068
We present an analysis of the Seyfert 2 galaxy NGC 1068 of archive data from the Spectrograph for INtegral Field Observations in the Near Infrared (SINFONI)-Very Large Telescope, in the HK bands with pixel scales of 0.1 (data set 1 – DS1) and 0.025 (DS2) arcsec. The data are revisited with a sophisticated data treatment, such as the differential atmospheric refraction correction and the application of a Butterworth filtering and deconvolution. The gain in the process is quantified by a significant improvement in the Strehl ratio and it shows that an unprecedented high spatial resolution is achieved. For DS1, a detailed study of the H2, [Fe ii] and [Si vi] emission lines reveals a three-phase gas morphology: (1) the low-velocity [Fe ii] emission representing the glowing wall of an hourglass structure, (2) the high-velocity compact blobs of low and high ionization emissions filling the hourglass volume and (3) the distribution of H2 molecular gas defines the thick and irregular walls of a bubble surrounding a cavity. Both the hourglass and the molecular emissions have an asymmetry caused by the fragmentation of the north-eastern molecular wall, closest to the active galactic nucleus, resulting in high-velocity compact blobs of ionized gas outside the bubble. The south-western part of the bubble is excavated by the jet, where the blobs remain confined and are blown along the bubble's inner boundary. We propose that those blobs are driven by a hot ‘secondary wind’ coming from the spot where the jet interacts and injects its energy in the molecular gas. The combination of a primary wind launched by the central source and the secondary wind is what we call a two-stage outflow. For DS2, we detected a [Si vi] outflow nearly coplanar to the maser disc and orthogonal to the CO outflow found by a previous study. Such unexpected scenario is interpreted as the interaction between the central radiation field and a two-phase gas density torus.
- 27 January 2016
- Published by Oxford University Press (OUP) in Monthly Notices of the Royal Astronomical Society
- Vol. 457 (1) , 949-970
Digging process in NGC 6951: the molecular disc bumped by the jet
We present a study of the central 200 pc of the galaxy NGC 6951, SAB(rs)bc, an active twin of the Milky Way, at a distance of 24 Mpc. Its nucleus has been observed in the optical with the Integral Field Unit of the Gemini Multi-Object Spectrograph, showing an outflow, and with the HST/ACS, revealing two extended structures with similar orientation, suggesting the presence of a collimating and/or obscuring structure. In order to ascertain this hypothesis, adaptive optics assisted NIR integral field spectroscopic observations were obtained with the Near-Infrared Integral Field Spectrograph in the Gemini North telescope. We detected a compact structure of H2 molecular gas, interpreted as a nearly edge-on disc with diameter of ∼47 pc, PA = 124° and velocity range from −40 to +40 km s−1. This disc is misaligned by 32° with respect to the radio jet and the ionization cones seen in the optical. There are two regions of turbulent gas, with position angles similar to the jet/cones, seen both in molecular and ionized phases; these regions are connected to the edges of the molecular disc and coincide with a high ratio of [N ii]/H α = 5, suggesting that these regions are shock excited, partially ionized or both. We explain these structures as a consequence of a ‘digging process’ that the jet inflicts on the disc, ejecting the molecular gas towards the ionization cones. The dynamical mass within 17 pc is estimated as 6.3 × 106 M⊙. This is an interesting case of an object presenting evidence of a connected feeding-feedback structure.
- 27 January 2016
- Published by Oxford University Press (OUP) in Monthly Notices of the Royal Astronomical Society
- Vol. 457 (1) , 949-970
Digging process in NGC 6951: the molecular disc bumped by the jet
We present a study of the central 200 pc of the galaxy NGC 6951, SAB(rs)bc, an active twin of the Milky Way, at a distance of 24 Mpc. Its nucleus has been observed in the optical with the Integral Field Unit of the Gemini Multi-Object Spectrograph, showing an outflow, and with the HST/ACS, revealing two extended structures with similar orientation, suggesting the presence of a collimating and/or obscuring structure. In order to ascertain this hypothesis, adaptive optics assisted NIR integral field spectroscopic observations were obtained with the Near-Infrared Integral Field Spectrograph in the Gemini North telescope. We detected a compact structure of H2 molecular gas, interpreted as a nearly edge-on disc with diameter of ∼47 pc, PA = 124° and velocity range from −40 to +40 km s−1. This disc is misaligned by 32° with respect to the radio jet and the ionization cones seen in the optical. There are two regions of turbulent gas, with position angles similar to the jet/cones, seen both in molecular and ionized phases; these regions are connected to the edges of the molecular disc and coincide with a high ratio of [N ii]/H α = 5, suggesting that these regions are shock excited, partially ionized or both. We explain these structures as a consequence of a ‘digging process’ that the jet inflicts on the disc, ejecting the molecular gas towards the ionization cones. The dynamical mass within 17 pc is estimated as 6.3 × 106 M⊙. This is an interesting case of an object presenting evidence of a connected feeding-feedback structure.
- 1 July 2014
- Published by Cambridge University Press (CUP) in Proceedings of the International Astronomical Union
- Vol. 10 (S309) , 329
The interaction of the outflow with the molecular disk in the Active Galactic Nucleus of NGC 6951
Context: we present a study of the central 200 pc of NGC 6951, in the optical and NIR, taken with the Gemini North Telescope integral field spectrographs, with resolution of ~ 0”.1 Methods: we used a set of image processing techniques, as the filtering of high spatial and spectral frequencies, Richardson-Lucy deconvolution and PCA Tomography (Steiner et al.2009) to map the distribution and kinematics of the emission lines. Results: we found a thick molecular disk, with the ionization cone highly misaligned.
- 1 July 2014
- Published by Cambridge University Press (CUP) in Proceedings of the International Astronomical Union
- Vol. 10 (S309) , 329
The interaction of the outflow with the molecular disk in the Active Galactic Nucleus of NGC 6951
Context: we present a study of the central 200 pc of NGC 6951, in the optical and NIR, taken with the Gemini North Telescope integral field spectrographs, with resolution of ~ 0”.1 Methods: we used a set of image processing techniques, as the filtering of high spatial and spectral frequencies, Richardson-Lucy deconvolution and PCA Tomography (Steiner et al.2009) to map the distribution and kinematics of the emission lines. Results: we found a thick molecular disk, with the ionization cone highly misaligned.