PUBLICATIONS :
·
Publications in refereed journals
- Published as 1rst author:
"Molecular Tracers
of Filamentary CO Emission Regions Surrounding the Central Galaxies of Clusters"
A&A, 2010a, In Press
Bayet, E.; Hartquist, T.W..; Williams, D.A.; Viti,
S.; & Bell, T.A.
Summary: Optical emission is detected from filaments around the central galaxies
of clusters of galaxies. The emission is possibly due to heating caused
by the dissipation of mechanical energy and/or by cosmic ray induced
ionisation. Our aim is to identify molecular species, other than CO (already
detected), that may emit detectable millimeter and submillimeter line features
that might serve as diagnostics of the dissipation and cosmic ray induced
ionisation. To do so, we have used the time-dependent UCL_PDR model
at appropriate pressures, for a range of dissipation and cosmic ray induced
ionisation rates and incident radiation fields. We have found that detections
of the galaxy cluster filaments in HCO+, C2H, and CN emissions and
further detections of them in HCN emissions would
provide significant
constraints on the dissipation and cosmic ray induced ionisation rates.
"Extragalactic CS survey"
ApJ, 2009c, 707, 126
Bayet, E.; Aladro, R.; Martin, S.; Viti, S.; &
Martin-Pintado, J.
Summary: This paper presents the most complete survey of CS lines in nearby
extragalactic sources obtained so far. We have observed more precisely
NGC 253, NGC 1068, IC 342, Henize 2-10, M 82, the Antennae Galaxies
and M 83. We use the CS molecule as a tracer of the densest gas component
of the ISM, following previous theoretical and observational studies by
Bayet et al. (2008a,b and 2009a). In this first paper, out of a series, we
analyze the CS data sample under both Local Thermodynamical
Equilibrium (LTE) and non-LTE (Large Velocity Gradient-LVG)
approximations. We show that except for M 83 and Overlap (a shifted
gas-rich position from the nucleus NGC 4039 in the Antennae Galaxies),
the observations in NGC 253, IC 342, M 82-NE, M 82-SW and
NGC 4038 are not well reproduced by a single set of gas component
properties and that, at least, two gas components are required. For each gas
component, we provide estimates of the corresponding kinetic temperature,
total CS column density and gas density.
"Are 12CO lines good indicators of star formation rate in galaxies?"
MNRAS, 2009b, 399, 264
Bayet, E.; Gerin, M.; Phillips, T.G. & Contursi,
A.
Summary: This paper presents, for the first time, a detailed analysis of observed
CO lines in sources from redshift = 0 to 6, testing the relevance of using
them as indicator of star formation activity. Empirical laws, very useful
tools for the preparation of future ALMA observations, are derived between
the CO luminosities (from J=1-0 to J=12-11) and the infrared luminosity
L(IR) (integrated from 8um to 1000um), usual probe of star formation
rate (SFR). The paper shows that the best indicator of SFR are high-J
rotational lines of CO such as the CO(7-6) line. Their luminosity indeed
showed the tightest correlation with L(IR), whatever the redshfit.
"Molecular tracers of PDR-dominated galaxies"
ApJ, 2009a, ApJ, 696, 1466
Bayet, E.; Viti, S.; Williams, D. A. & Rawlings,
J.M.C.
Summary: This paper presents theoretical results from the UCL_PDR model (time
dependent) : We have identified for various types of galaxies (starburst,
low-metallicity, ...) the molecules (others than C and CO) which are
signatures of a Photon-Dominated (PDR) gas. We predict which are those
most appropriate to been observed with respect to the galaxy type. We
also present the variation of the molecular chemical relative abundances
with respect to physical conditions seen in these various types of galaxies.
"Tracing high density gas in M 82 and NGC 4038"
ApJL, 2008b, 685, 35
Bayet, E.; Lintott, C.; Viti, S.; Martin-Pintado,J.; Martin, S.; Williams, D. A.
& Rawlings, J.M.C.
Summary: This article shows for the first time the detections of the high frequency
lines of the CS molecule obtained in the nucleus of the starburst galaxy
M 82 and in NGC 4038 (one of the nuclei of the merging system of the
Antennae Galaxies). In particular, in M 82, the CS(7-6) detection confirms
the presence of a very dense gas having physical properties significantly
different from those obtained for lower-J lines of CS.
"Molecular tracers of high-mass star formation in external galaxies"
ApJ, 2008a, 676, 978
Bayet, E.; Viti, S.; Williams, D. A. & Rawlings,
J.M.C.
Summary: This paper summarizes a theoretical study performed with the
UCL_Chem model (time dependent) in order to determine the chemical
properties of the very dense gas in extragalactic star formation regions.
We predict for the first time the most relevant molecules, tracers of this
very dense gas composant, to observe in various morphological types of
galaxies (starburst, AGN, low-metallicity, ...). We also studied the variation
of the molecular chemical relative abundances with respect to physical
conditions seen in galaxies.
"A
survey of submillimeter C and CO lines in nearby galaxies"
A&A, 2006, 460, 467
Bayet, E.; Gerin, M.; Phillips, T.G. & Contursi,
A.
Summary: This paper shows the most complete to date sample of high frequency
C and CO lines ever taken in about ten nearby galaxies. Through an LVG
and PDR analysis of the data, both included in the paper,we have determined
the average physical properties of the molecular gas corresponding to such
emission seen in each source.
"The Submillimeter C and CO lines in
Henize 2-10 and NGC 253"
A&A, 2004, 427, 45
Bayet, E.; Gerin, M.; Phillips, T.G. & Contursi,
A.
Summary: This article shows the first sample of high frequency C and CO lines
ever taken in the irregular galaxy Henize 2-10and the starburst galaxy
NGC 253. Through an LVG and PDR analysis of the data, both included
in the paper, we have determined the average physical properties of the
molecular gas corresponding to such emission seen in these two sources.
- Published as co-author:
"CS, HC3N and CH3CCH multi-line analyses toward starburst galaxies
- The evolution of cloud structures in the central regions of galaxies"
A&A, 2010, In Press
Aladro R. et al.
Summary: This paper presents the first observational attempt to understand the
evolution of starburst galaxies as seen by the evolution of the properties of
its molecular gas. This work has been realised via the modelling (non-LTE
i.e. LVG models) of observations of molecular species tracing different
gas component.
"Chemical modelling of L183 (=L134N): an estimate of the ortho/para H2 ratio"
A&A, 2009, 494, 623
Pagani, L. et al.
Summary: This paper presents the modelisation of the pre-stellar core L183 and
more especially its chemical modelisation from observations of non-deuterated
and deuterated molecules for which I have participated. This interest of this
paper is also in the update of the ortho/para H2 reaction rates, essential in
the models used.
"Destruction of molecular gas reservoirs in early-type galaxies by AGN-feedback"
ApJ, 2009, 690, 1672
Schawinski, K. et al.
Summary: This paper confirsm observationally the link existing between the destruction
of the reservoirs of gas caontained in the nucleus of active galaxies and their
AGN counterpart. This study is performed via CO observations in the
submillimetric-millimetric where my expertise is concentrated.
"Photon-dominated regions in the spiral arms of M 83 and M 51"
A&A, 2005, 441, 961
Kramer, C. et al.
Summary: This paper focusses on the study of the activity of star formation in
spiral arms in galaxies and in particular in those of M 83 and M 51.
The data used here (CO line emissions) for M 83 are from my PhD
Thesis work.
·
Submitted Articles
- As 1rst author:
"Deuterated
species in extragalactic star-forming regions"
MNRAS, 2010c, Submitted
Bayet, E.; Awad, Z. & Viti, S.
Summary: For the first time, we present a theoretical study of the deuterated species
in external galaxies. We follow closely in this paper the goals achieved
previously by Bayet et al. (2008a, 2009a), but with an improved version
of their chemical network. Indeed, we have included in our present study
~100 deuterated molecules, those known to play the most important role
in the chemistry when the gas is in star-forming phase (i.e. dense and cold).
When the usual tracers of dense gas such as CO and CS are depleted onto
grain, we thus identified in this paper which deuterated molecules are the
most likely to be detectable, and the most likely to trace this gas, in various
types of galaxies (starburst, AGN, low-metallicity,...). In addition to provide
clues of the evolution of the fractional abundances of deuterated species
with respect to the gas density, the FUV radiation field, the temperature,
the cosmic ray ionisation rate,..., we also provide key predictions
concerning their corresponding D/H ratios.
"CS line profiles
in hot cores"
ApJ, 2010b, Re-Submitted
Bayet, E.; Yates, J. & Viti, S.
Summary: We present a theoretical study of CS line profiles in hot cores. We
provide estimates of line fluxes from the CS(1-0) to the
CS(15-14)
transitions and presents the variation of these fluxes as a function
of size of the hot core. In addition, a sensitivity study is performed
on the CS line emissions, where we investigate the influence of the
age of the hot core, its size, its density and temperature profiles. We
find that i) the CS(1-0) transition is a better tracer of the Envelope of
the hot core whereas the higher-J CS lines trace the ultra-compact core;
ii) the peak tempertaure of the CS transitions is a good indicator of the
temperature inside the hot core; iii) in the Envelope, the older the hot core
the stronger the self-absorption of CS; iv) the fractional abundance of CS
is highest in the innest parts of the ultra-compact core, confirming the CS
molecule as one of the best tracer of very dense gas.
- As co-author:
"A comparison of
dense molecular gas tracers towards the Galactic starburst analogue W49A"
A&A, 2010, Re-Submitted
Roberts H. et al.
·
Papers in preparation
- As 1rst author:
- As co-author:
"Deuterated chemistry in galactic warm and hot cores"
MNRAS, 2010,
Awad, Z. et al.
·
Conferences Proceedings
- Bayet, E.; Viti, S.; Lintott, C.; Martin-Pintado, J.; Martin, S.; Williams, D. A. and Rawlings, J.M.C.; 2009; EAS, To come, National Astronomical
Meeting, Belfast (UK): Molecular tracers in extragalactic star-forming region (invited talk).
- Bayet, E.; Viti, S.; Lintott, C.; Martin-Pintado, J.; Martin, S.; Williams, D. A. and Rawlings, J.M.C.; 2008; EdP-Sciences, Conference Series (To come):
The Molecular Universe: an International Meeting on the Physics and Chemistry of the Interstellar Medium; Arcachon (France): Molecular tracers in
extragalactic star-forming regions.
- Bayet, E.; Viti, S.; Williams, D. A. and Rawlings, J.M.C.; 2007; EdP-Sciences, Conference Series : FIR’07: Far-Infrared and Submillimeter Emission
of the Interstellar Medium: Models meet extragalactic and Galactic Observations; Bonn (Germany): Hot core chemistry in extragalactic star
formation regions.
- Bayet, E.; Berne, O.; Joblin, C.; Gerin, M.; García-Burillo, S. and Fuente, A.; 2007; EdP-Sciences, Conference Series : FIR’07: Far-Infrared
and Submillimeter Emission of the Interstellar Medium: Models meet extragalactic and Galactic Observations; Bonn (Germany): Comparison CO-
PAH+/PAH0/VSGs emissions in external galaxies (Chosen as the cover picture of the proceeding book).
- Bayet, E.; Bell, T.; Viti, S.; Rawlings, J.; Roueff, E. and Williams, D.; 2007; Conference proceeding, p. 311: Molecules in Space and in Laboratory;
Paris (France): Modelling the chemistry of external galaxies (invited talk).
- Bayet, E.; Le Bourlot, J.; Roueff, E. & Le Petit, F.; 2006 ; EdP-Sciences, Conference Series (To come) : Colloque général du Programme National de
Physique et de Chimie du Milieu Interstellaire (PCMI), Grenoble (France): Effects of the improvements of photo-destruction rates calculations in
the PDR models predictions.
- Bayet, E.; Le Bourlot, J.; Roueff, E. & Le Petit, F.; 2006 ; AIP conference Proceedings, vol. 901, p. 253 : ICAMDATA05, 7ème Rencontre de
l’Observatoire, Meudon (France): Importance of the molecular photo-destruction cross sections to model the ISM
- Bayet, E.; Gerin, M.; Phillips, T.G. ; Le Bourlot, J.; & Le Petit, F.; 2006; EAS Publication Series, vol. 24, p. 279: CRAL-Chemodynamics:
From First Stars to Local Galaxies, Lyon (France): Star Formation Feedback on the ISM Properties.
- Bayet, E.; Gerin, M.; Phillips, T.G. & Contursi, A., 2005; EdP-Sciences, Conference Series, SF2A-2005, p. 383: Semaine de l'Astrophysique
Française, Paris (France): The C and CO cooling rates in nearby galaxies, study of warm and dense molecular gas.
- Bayet, E.; Rabasse, J.F & Gerin, M.; 2005 ; EdP-Sciences, Conference Series, SF2A-2005, p. 391: Semaine de l'Astrophysique
Française, Paris (France): SubMIR - a submillimeter and IR observations database.
- Bayet, E.; Gerin, M.; Phillips, T.G. & Contursi, A.; 2005; Cambridge University Press, p. 169: Astrochemistry Throughout the Universe:
Recent Successes and Current Challenges, International Astronomical Union. Symposium no. 231, Asilomar (California- USA): CO and C
cooling in galaxy nuclei, new tracers of the star forming activity?
- Bayet, E.; Gerin, M.; Phillips, T.G. & Contursi, A., 2005; A. Wilson. ESA SP-577, p. 343: The Dusty and molecular Universe - A prelude
to Herschel and ALMA, Paris (France): The contribution of the submillimeter lines of CO and C in the cooling in the nearby galaxies.
- Bayet, E.; Gerin, M.; Phillips, T.G. & Contursi, A., 2004; EdP-Sciences, Conference Series SF2A-2004, p. 487: Semaine de l'Astrophysique
Française, Paris (France): The C and CO lines in nearby galaxies, study of interstellar medium cooling.
- Bayet, E.; Gerin, M.; Phillips, T.G. & Contursi, A., 2004; ASP Conf. Series, vol. 320, p. 39: The neutral ISM in starburst galaxies,
Maarstrand (Sweden): The Submillimeter spectrum of NGC 253 and Henize 2-10.
