Publications by Patrick Roche


The magnetic field in the central parsec of the Galaxy

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 476 (2018) 235-245

PF Roche, E Lopez-Rodriguez, CM Telesco, R Schodel, C Packham


High resolution imaging of the magnetic field in the central parsec of the Galaxy

Planetary and Space Science (2018)

PF Roche, E Lopez-Rodriguez, CM Telesco, R Schödel, C Packham

© 2018 We discuss a high resolution (FWHM∼0.45 arcsec) image of the emissive polarization from warm dust in the minispiral in the Galactic Centre and discuss the implications for the magnetic field in the dusty filaments. The image was obtained at a wavelength of 12.5 μm with the CanariCam multimode mid-infrared imager on the Gran Telescopio Canarias. It confirms the results obtained from previous observations but also reveals new details of the polarization structures. In particular, we identify regions of coherent magnetic field emission at position angles of ∼45oto the predominantly north–south run of field lines in the Northern Arm which may be related to orbital motions inclined to the general flow of the Northern Arm. The luminous stars that have been identified as bow-shock sources in the Northern Arm do not disrupt or dilute the field but are linked by a coherent field structure, implying that the winds from these objects may push and compress the field but do not overwhelm it. The magnetic field in the low surface brightness regions in the East-West Bar to the south of SgrA* lies along the Bar, but the brighter regions generally have different polarization position angles, suggesting that they are distinct structures. In the region of the Northern Arm sampled here, there is only a weak correlation between the intensity of the emission and the degree of polarization. This is consistent with saturated grain alignment where the degree of polarization depends on geometric effects, including the angle of inclination of the field to the line of sight and superposition of filaments with different field directions, rather than the alignment efficiency.


ALMA spectral survey of Supernova 1987A-molecular inventory, chemistry, dynamics and explosive nucleosynthesis

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 469 (2017) 3347-3362

M Matsuura, R Indebetouw, S Woosley, V Bujarrabal, FJ Abellan, R McCray, J Kamenetzky, C Fransson, MJ Barlow, HL Gomez, P Cigan, I De Looze, J Spyromilio, L Staveley-Smith, G Zanardo, P Roche, J Larsson, S Viti, JT van Loon, JC Wheeler, M Baes, R Chevalier, P Lundqvist, JM Marcaide, E Dwek, M Meixner, C-Y Ng, G Sonneborn, J Yates


ALMA observations of Molecules in Supernova 1987A

Proceedings of the International Astronomical Union 12 (2017) 294-299

M Matsuura, R Indebetouw, S Woosley, V Bujarrabal, FJ Abellán, R McCray, J Kamenetzky, C Fransson, MJ Barlow, HL Gomez, P Cigan, I De Looze, J Spyromilio, L Staveley-Smith, G Zanardo, P Roche, J Larsson, S Viti, JT Van Loon, JC Wheeler, M Baes, R Chevalier, P Lundqvist, JM Marcaide, E Dwek, M Meixner, CY Ng, G Sonneborn, J Yates

© 2017 International Astronomical Union. Supernova (SN) 1987A has provided a unique opportunity to study how SN ejecta evolve in 30 years time scale. We report our ALMA spectral observations of SN 1987A, taken in 2014, 2015 and 2016, with detections of CO, 28SiO, HCO+ and SO, with weaker lines of 29SiO. We find a dip in the SiO line profiles, suggesting that the ejecta morphology is likely elongated. The difference of the CO and SiO line profiles is consistent with hydrodynamic simulations, which show that Rayleigh-Taylor instabilities causes mixing of gas, with heavier elements much more disturbed, making more elongated structure. Using 28SiO and its isotopologues, Si isotope ratios were estimated for the first time in SN 1987A. The estimated ratios appear to be consistent with theoretical predictions of inefficient formation of neutron rich atoms at lower metallicity, such as observed in the Large Magellanic Cloud (about half a solar metallicity). The deduced large HCO+ mass and small SiS mass, which are inconsistent to the predictions of chemical model, might be explained by some mixing of elements immediately after the explosion. The mixing might have made some hydrogen from the envelope to sink into carbon and oxygen-rich zone during early days after the explosion, enabling the formation of a substantial mass of HCO+. Oxygen atoms may penetrate into silicon and sulphur zone, suppressing formation of SiS. Our ALMA observations open up a new window to investigate chemistry, dynamics and explosive-nucleosynthesis in supernovae.


A mid-infrared statistical investigation of clumpy torus model predictions

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 470 (2017) 2578-2598

J Garcia-Gonzalez, A Alonso-Herrero, SF Honig, A Hernan-Caballero, C Ramos Almeida, NA Levenson, PF Roche, O Gonzalez-Martin, C Packham, M Kishimoto


Infrared polarimetry of Mrk 231: scattering off hot dust grains in the central core

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 464 (2017) 1762-1770

E Lopez-Rodriguez, C Packham, TJ Jones, R Siebenmorgen, PF Roche, NA Levenson, A Alonso-Herrero, E Perlman, K Ichikawa, C Ramos Almeida, O Gonzalez-Martin, R Nikutta, M Martinez-Paredez, D Shenoy, MS Gordon, CM Telesco


Very Deep inside the SN 1987A Core Ejecta: Molecular Structures Seen in 3D

ASTROPHYSICAL JOURNAL LETTERS 842 (2017) ARTN L24

FJ Abellan, R Indebetouw, JM Marcaide, M Gabler, C Fransson, J Spyromilio, DN Burrows, R Chevalier, P Cigan, BM Gaensler, HL Gomez, H-T Janka, R Kirshner, J Larsson, P Lundqvist, M Matsuura, R McCray, C-Y Ng, S Park, P Roche, L Staveley-Smith, JT van Loon, JC Wheeler, SE Woosley


The complex evolutionary paths of local infrared bright galaxies: a high-angular resolution mid-infrared view

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 463 (2016) 2405-2424

A Alonso-Herrero, R Poulton, PF Roche, A Hernan-Caballero, I Aretxaga, M Martinez-Paredes, C Ramos Almeida, M Pereira-Santaella, T Diaz-Santos, NA Levenson, C Packham, L Colina, P Esquej, O Gonzalez-Martin, K Ichikawa, M Imanishi, JM Rodriguez Espinosa, C Telesco


A mid-infrared spectroscopic atlas of local active galactic nuclei on sub-arcsecond resolution using GTC/CanariCam

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 455 (2016) 563-583

A Alonso-Herrero, P Esquej, PF Roche, C Ramos Almeida, O Gonzalez-Martin, C Packham, NA Levenson, RE Mason, A Hernan-Caballero, M Pereira-Santaella, C Alvarez, I Aretxaga, E Lopez-Rodriguez, L Colina, T Diaz-Santos, M Imanishi, JM Rodriguez Espinosa, E Perlman


The nuclear and integrated far-infrared emission of nearby Seyfert galaxies

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 458 (2016) 4512-4529

J Garcia-Gonzalez, A Alonso-Herrero, A Hernan-Caballero, M Pereira-Santaella, C Ramos-Almeida, JA Acosta-Pulido, T Diaz-Santos, P Esquej, O Gonzalez-Martin, K Ichikawa, E Lopez-Rodriguez, M Povic, PF Roche, M Sanchez-Portal


Mid-infrared imaging- and spectro-polarimetric subarcsecond observations of NGC 1068

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 458 (2016) 3851-3866

E Lopez-Rodriguez, C Packham, PF Roche, A Alonso-Herrero, T Diaz-Santos, R Nikutta, O Gonzalez-Martin, CA Alvarez, P Esquej, JM Rodriguez Espinosa, E Perlman, C Ramos Almeida, CM Telesco


MID-IR SPECTRA OF TYPE Ia SN 2014J IN M82 SPANNING THE FIRST 4 MONTHS

ASTROPHYSICAL JOURNAL 798 (2015) ARTN 93

CM Telesco, P Hoeflich, D Li, C Alvarez, CM Wright, PJ Barnes, S Fernandez, JH Hough, NA Levenson, N Marinas, C Packham, E Pantin, R Rebolo, P Roche, H Zhang


The nuclear and extended infrared emission of the Seyfert galaxy NGC 2992 and the interacting system Arp 245

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 449 (2015) 1309-1326

I Garcia-Bernete, C Ramos Almeida, JA Acosta-Pulido, A Alonso-Herrero, M Sanchez-Portal, M Castillo, M Pereira-Santaella, P Esquej, O Gonzalez-Martin, T Diaz-Santos, P Roche, S Fisher, M Povic, AM Perez Garcia, I Valtchanov, C Packham, NA Levenson


The silicate absorption profile in the interstellar medium towards the heavily obscured nucleus of NGC 4418

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 449 (2015) 2598-2603

PF Roche, A Alonso-Herrero, O Gonzalez-Martin


Magnetic field structures in star-forming regions: mid-infrared imaging polarimetry of K3-50

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 453 (2015) 2622-2636

P Barnes, D Li, C Telesco, N Tanakul, N Marinas, C Wright, C Packham, E Pantin, P Roche, J Hough


A mid-infrared view of the inner parsecs of the Seyfert galaxy Mrk 1066 using CanariCam/GTC

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 445 (2014) 1130-1143

C Ramos Almeida, A Alonso-Herrero, P Esquej, O Gonzalez-Martin, RA Riffel, I Garcia-Bernete, JM Rodriguez Espinosa, C Packham, NA Levenson, P Roche, T Diaz-Santos, I Aretxaga, C Alvarez


Nuclear star formation activity and black hole accretion in nearby seyfert galaxies

Astrophysical Journal 780 (2014)

P Esquej, A Alonso-Herrero, O González-Martín, SF Hönig, A Hernán-Caballero, P Roche, C Ramos Almeida, RE Mason, T Díaz-Santos, NA Levenson, I Aretxaga, JM Rodríguez Espinosa, C Packham

Recent theoretical and observational works indicate the presence of a correlation between the star-formation rate (SFR) and active galactic nucleus (AGN) luminosity (and, therefore, the black hole accretion rate, ṀBH) of Seyfert galaxies. This suggests a physical connection between the gas-forming stars on kpc scales and the gas on sub-pc scales that is feeding the black hole. We compiled the largest sample of Seyfert galaxies to date with high angular resolution (∼0.′4-0. ′8) mid-infrared (8-13μm) spectroscopy. The sample includes 29 Seyfert galaxies drawn from the AGN Revised Shapley-Ames catalog. At a median distance of 33 Mpc, our data allow us to probe nuclear regions on scales of∼65 pc (median value).We found no general evidence of suppression of the 11.3μmpolycyclic aromatic hydrocarbon (PAH) emission in the vicinity of these AGN, and we used this feature as a proxy for the SFR.We detected the 11.3μm PAH feature in the nuclear spectra of 45% of our sample. The derived nuclear SFRs are, on average, five times lower than those measured in circumnuclear regions of 600 pc in size (median value). However, the projected nuclear SFR densities (median value of 22M⊙ yr-1 kpc-2) are a factor of 20 higher than those measured on circumnuclear scales. This indicates that the SF activity per unit area in the central ∼65 pc region of Seyfert galaxies is much higher than at larger distances from their nuclei. We studied the connection between the nuclear SFR and?ṀBH and showed that numerical simulations reproduce our observed relation fairly well. © 2014. The American Astronomical Society. All rights reserved. Printed in the U.S.A.


Nuclear 11.3 mu m PAH emission in local active galactic nuclei

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 443 (2014) 2766-2782

A Alonso-Herrero, C Ramos Almeida, P Esquej, PF Roche, A Hernan-Caballero, SF Honig, O Gonzalez-Martin, I Aretxaga, RE Mason, C Packham, NA Levenson, JM Rodriguez Espinosa, R Siebenmorgen, M Pereira-Santaella, T Diaz-Santos, L Colina, C Alvarez, CM Telesco


Towards precise ages and masses of Free Floating Planetary Mass Brown Dwarfs

Monthly Notices of the Royal Astronomical Society 435 (2013) 2650-2664

JI Canty, PW Lucas, PF Roche, DJ Pinfield


Uncovering the deeply embedded active galactic nucleus activity in the nuclear regions of the interacting galaxy Arp 299

Astrophysical Journal Letters 779 (2013)

A Alonso-Herrero, PF Roche, P Esquej, O González-Martín, M Pereira-Santaella, C Ramos Almeida, NA Levenson, C Packham, A Asensio Ramos, RE Mason, JM Rodríguez Espinosa, C Alvarez, L Colina, I Aretxaga, T Díaz-Santos, E Perlman, CM Telesco

We present mid-infrared (MIR) 8-13 μm spectroscopy of the nuclear regions of the interacting galaxy Arp 299 (IC 694+NGC 3690) obtained with CanariCam (CC) on the 10.4 m Gran Telescopio Canarias (GTC). The high angular resolution (∼0.″3-0.″6) of the data allows us to probe nuclear physical scales between 60 and 120 pc, which is a factor of 10 improvement over previous MIR spectroscopic observations of this system. The GTC/CC spectroscopy displays evidence of deeply embedded active galactic nucleus (AGN) activity in both nuclei. The GTC/CC nuclear spectrum of NGC 3690/Arp 299-B1 can be explained as emission from AGN-heated dust in a clumpy torus with both a high covering factor and high extinction along the line of sight. The estimated bolometric luminosity of the AGN in NGC 3690 is 3.2 ± 0.6 × 1044 erg s-1. The nuclear GTC/CC spectrum of IC 694/Arp 299-A shows 11.3 μm polycyclic aromatic hydrocarbon emission stemming from a deeply embedded (AV ∼ 24 mag) region of less than 120 pc in size. There is also a continuum-emitting dust component. If associated with the putative AGN in IC 694, we estimate that it would be approximately five times less luminous than the AGN in NGC 3690. The presence of dual AGN activity makes Arp 299 a good example to study such phenomena in the early coalescence phase of interacting galaxies. © 2013. The American Astronomical Society. All rights reserved.

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