Issue 10 | August 2014

AstroPAHA Newsletter on Astronomical PAHs

EditorialDear Colleagues,

Welcome to the 10th release of AstroPAH. This August cover features bottles containingPAH samples as Picture of the Month. AstroPAH this month is modest due to the holidayseason and as such, our in Focus is on holiday. Nevertheless, science never stops, so we dohave a couple of very interesting abstracts; PAH detection in various types of galaxies and theeffect of PAH edge structure at 12.7µm. We would further like to draw your attention to theupcoming International Conference on Interstellar Dust, Molecules and Chemistry announcedin our Scientific Meetings section.

We thank you all for your contributions and please keep them coming. You can send yourcontributions to AstroPAH any time. The deadline for contributions to appear in the next issueis 12 September 2014. The next issue of AstroPAH will be out on 23 September 2014.

For more information on AstroPAH, visit our website:

http://astropah-news.strw.leidenuniv.nl.

Best regards

The Editorial Team

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AstroPAH Newsletter

EDITORIAL BOARD:

Editor-in-ChiefProf. Alexander TielensLeiden Observatory (The Netherlands)

Executive EditorDr. Isabel AlemanLeiden Observatory (The Netherlands)

EditorDr. Alessandra CandianLeiden Observatory (The Netherlands)

EditorDr. Elisabetta MicelottaInstitut d’Astrophysique SpatialeCNRS/Universite Paris-Sud (France)

EditorDr. Annemieke PetrignaniLeiden Observatory andRadboud University Nijmegen(The Netherlands)

EditorDr. Ella Sciamma-O’BrienNASA Ames Research Center (USA)

WEBSITE:http://astropah-news.strw.leidenuniv.nl

CONTACT:astropah@strw.leidenuniv.nl

SUBSCRIBE:Click here to subscribe to AstroPAH

Contents

PAH Picture of the Month 1

Editorial 2

Recent Papers 4

Scientific Meetings 6

PAH Picture of the Month

PAH samples for laboratory use come in con-tainers of different shapes and sizes. Thesesamples may be liquid or solid. A numberof techniques can be used to obtain PAHsin the gas phase, for example heating in anoven, laser desorption or electro-spray ioni-sation. The flasks shown are a few of themany samples of PAH and derivative speciesthat are available at the FELIX Facility inNijmegen, the Netherlands. From left toright: pentacene, anthracene, methylquino-line, 2,3-benzanthracene, tetraphenylene,and fullerene.

Credits: Annemieke Petrignani and IsabelAleman

3

Recent Papers

Polycyclic Aromatic Hydrocarbons with Armchair Edges andthe 12.7 µm bandA. Candian1, P.J. Sarre2 and A.G.G.M. Tielens1

1 Leiden Observatory, Niels Bohrweg 2, Leiden, The Netherlands2 School of Chemistry, The University of Nottingham, Nottingham, UK

In this Letter we report the results of Density Functional Theory (DFT) calculations on medium-sized neutral Polycyclic Aromatic Hydrocarbon (PAH) molecules with armchair edges. ThesePAH molecules possess strong C-H stretching and bending modes around 3 µm and in thefingerprint region (10-15 µm), and also strong ring deformation modes around 12.7 µm. Pe-rusal of the entries in the NASA Ames PAHs Database (Bauschlicher et al., 2010) shows thatring deformation modes of PAHs are common - although generally weak. We then proposethat armchair PAHs with NC >65 are responsible for the 12.7 µm Aromatic Infrared Band in Hiiregions and discuss astrophysical implications in the context of the PAH life-cycle.

E-mail: candian@strw.leidenuniv.nlApJ, 2014, 791, L10http://iopscience.iop.org/2041-8205/791/1/L10/article

Polycyclic aromatic hydrocarbon feature deficit of starburstgalaxies in the AKARI North Ecliptic Pole Deep fieldK. Murata1,2, H. Matsuhara1,2, H. Inami3, T. Wada1, T. Goto4, L. Armus 5,C. Pearson6,7,8, S. Serjeant7, T. Miyaji9

1 Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, 229-8510Kanagawa, Japan2 Department of Space and Astronautical Science, The Graduate University for Advanced Studies, Japan3 National Optical Astronomy Observatory, Tucson, AZ 85719, USA4 Institute of Astronomy and Department of Physics, National Tsing Hua University, No. 101, Section 2, Kuang-FuRoad, Hsinchu 30013, Taiwan, R.O.C5 Spitzer Science Center, Calfornia Institute of Technology, MS 220-6, Pasadena, CA 911256 RAL Space, STFC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, UK7 Department of Physical Sciences, The Open University, Milton Keynes, MK7 6AA, UK

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8 Oxford Astrophysics, Oxford University, Keble Road, Oxford OX1 3RH, UK9 Instituto de Astronomıa, Universidad Nacional Autonoma de Mexico, Ensenada, Baja California, Mexico

We study the behaviour of Polycyclic Aromatic Hydrocarbon emission in galaxies at z =0.3 − 1.4 using 1868 samples from the revised catalogue of AKARI North Ecliptic Pole deepsurvey. The continuous filter coverage at 2-24 µm makes it possible to measure 8 µm luminosity,which is dominated by Polycyclic Aromatic Hydrocarbon emission, for galaxies at up to z = 2.We compare the IR8 (≡ LIR/L(8)) and 8 µm to 4.5 µm luminosity ratio (νL(8)/νL(4.5)) withthe starburstiness, RSB, defined as excess of specific star formation rate over that of main-sequence galaxy. All AGN candidates were excluded from our sample using an SED fitting.We found νL(8)/νL(4.5) increases with starburstiness at log RSB <0.5, and stays constant athigher starburstiness. On the other hand, IR8 is constant at log RSB < 0, while it increaseswith starburstiness at log RSB >0. This behaviour is seen in all redshift range of our study.These results indicate that starburst galaxies have deficient Polycyclic Aromatic Hydrocarbonemission compared with main-sequence galaxies. We also find galaxies with extremely highνL(8)/νL(4.5) ratio have only moderate starburstiness. These results suggest that starburstgalaxies have compact star-forming regions with intense radiation which destroys PAHs and/orhave dusty HII regions resulting in a lack of ionising photons.

E-mail: murata@ir.isas.jaxa.jpA&A, 566, id.A136 (2014)http://ads.nao.ac.jp/abs/2014A%26A...566A.136M

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Scientific Meetings

International Conference on Interstellar Dust,Molecules and Chemistry (IDMC-2014)

Tezpur, Assam, India15 - 18 December, 2014

Objectives:

The interstellar medium (ISM) consists of a mixture of ions, atoms, molecules, dust grains,cosmic rays, and (galactic) magnetic fields. Thus it is a treasure trove for the study of a widevariety of physical phenomenon. The ISM also plays a crucial role in star and planet formation.The interplay between stars and the ISM determines the lifespan of active star formation andevolution. Recent advances in observational, laboratory, theoretical studies have opened upseveral avenues of work, made attractive by the possibilities of diverse interdisciplinary interac-tions. The conference intends to provide platform for expert discussions and presentations withample opportunities for young and motivated students and researchers to interact and to takeup challenging problems in this field.

Broad Topics:

• ISM Overview - Constituents, Observational diagnostics• Dust in ISM - Composition, Starlight extinction - observations & models• ISM Molecules and Spectroscopy• Star Formation - The Role of the ISM• Dust and molecules in external galaxies• Laboratory Astrophysics and Astrochemistry• Quantum Chemistry

Invited Speakers:

Gazi Ahmed, Tezpur University, IndiaB. G. Anandarao, PRL, Ahmedabad, IndiaRobert Botet, University of Paris, FranceJan Cami, University of Western Ontario, CanadaJose Cernicharo, INTA, Madrid, SpainRanjan Gupta, IUCAA, Pune, IndiaEric Herbst, University of Virginia, USA

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Christine Joblin, University of Toulouse, FranceAigen Li, University of Missouri, USAAshish Mahabal, Caltech, USAJayant Murthy, IIA, Bangalore, IndiaD. K. Ojha, TIFR, Mumbai, IndiaMarina Prokopyeva, St. Petersburgh, RussiaShantanu Rastogi, Gorakhpur University, IndiaGael Rouille, University of Jena, GermanyItsuki Sakon, University of Tokyo, JapanAshoke Sen, Assam University, IndiaU. J. Sofia, American University, WashingtonN. C. Wickramasinghe, Cardiff University, U.KD. B. Vaidya, Ahmedabad, India

Important Dates:

Participation is limited so intention to participate may be communicated by October 01, 2014.Abstracts must be submitted by October 15, 2014

Scientific Organising Commitee (SOC):

A. J. Choudhury, Tezpur, IndiaRanjan Gupta, IUCAA, IndiaThomas Henning, MPIA, Germany (Co-Chair)Ajit Kembhavi, IUCAA, IndiaEric Herbst, Virginia, USAHiroshi Kimura, CPS, JapanShantanu Rastogi, Gorakhpur, India (Co-Chair)Peter Sarre, Nottingham, UKAshok Sen, Silcher, IndiaTakashi Onaka, Tokyo, Japan

Contact:

E-mail: emailto:2014.idmc@gmail.comWebsite: http://www.iucaa.ernet.in/∼idmc2014

AstroPAH Newsletter

http://astropah-news.strw.leidenuniv.nlastropah@strw.leidenuniv.nl

Next issue: 23 September 2014Submission deadline: 12 September 2014

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