scholarly journals A relationship of polycyclic aromatic hydrocarbon features with galaxy merger in star-forming galaxies at z < 0.2

2017 ◽  
Vol 472 (1) ◽  
pp. 39-50 ◽  
Author(s):  
Katsuhiro L. Murata ◽  
Rika Yamada ◽  
Shinki Oyabu ◽  
Hidehiro Kaneda ◽  
Daisuke Ishihara ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Star Forming ◽  
Polycyclic Aromatic ◽  
Relationship Of

scholarly journals The Spitzer spectroscopic survey of the Small Magellanic Cloud: polycyclic aromatic hydrocarbon emission from SMC star-forming regions

2008 ◽  
Vol 4 (S256) ◽  
pp. 160-165
Author(s):  
Karin M. Sandstrom ◽  
Alberto D. Bolatto ◽  
Snežana Stanimirović ◽  
J. D. T. Smith ◽  
Jacco Th. van Loon ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Physical State ◽  
Magellanic Cloud ◽  
Small Magellanic Cloud ◽  
Star Forming ◽  
Star Forming Regions ◽  
Polycyclic Aromatic ◽  
Hydrocarbon Emission ◽  
Low Metallicity

AbstractBecause of its proximity, the Small Magellanic Cloud provides a unique opportunity to map the polycyclic aromatic hydrocarbon (PAH) emission from photo-dissociation regions (PDRs) in a low-metallicity (12 + log(O/H) ~ 8) galaxy at high spatial resolution in order to learn about their abundance and physical state. We present mid-IR spectral mapping observations of star-forming regions in the Small Magellanic Cloud obtained as part of the Spitzer Spectroscopic Survey of the SMC (S4MC) project. These observations allow us to map the distribution of PAH emission in these regions and the measure the variation of PAH band strengths with local physical conditions. In these proceedings we discuss preliminary results on the physical state of the PAHs, in particular their ionization fraction.

scholarly journals Polycyclic aromatic hydrocarbon excitation in nearby spiral galaxies

2020 ◽  
Vol 496 (2) ◽  
pp. 1393-1417 ◽  
Author(s):  
G J Bendo ◽  
N Lu ◽  
A Zijlstra
Keyword(s):  
Star Formation ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Spiral Galaxies ◽  
Dust Emission ◽  
Stellar Populations ◽  
Mid Infrared ◽  
Star Forming ◽  
Evolved Stars ◽  
Polycyclic Aromatic

ABSTRACT We have examined polycyclic aromatic hydrocarbon (PAH) excitation in a sample of 25 nearby face-on spiral galaxies using the ratio of mid-infrared PAH emission to dust mass. Within 11 of the galaxies, we found that the PAH excitation was straightforwardly linked to ultraviolet (UV) or mid-infrared star formation tracers, which, along with other results studying the relation of PAH emission to star formation, indicates that the PAHs are most strongly excited in dusty shells around the star-forming (SF) regions. Within another five galaxies, the PAH emission is enhanced around SF regions only at specific galactocentric radii. In six more galaxies, PAH excitation is more strongly correlated with the evolved stellar populations as traced by 3.6 μm emission. The results for the remaining three galaxies were ambiguous. The radial gradients of the PAH/dust ratios were generally not linked to log(O/H) gradients except when the log(O/H) gradients were relatively steep. Galaxies in which PAHs were excited by evolved stars had relatively high far-UV to mid-infrared ratios, implying that variations in the link between PAH excitation and different stellar populations are connected to changes in dust attenuation within galaxies. Alternately, differences in morphology could make it more likely that PAHs are excited by evolved stars, as five of the six galaxies where this occurs are late-type flocculent spiral galaxies. These heterogeneous results demonstrate the complexity of describing PAH excitation and have broad implications for using PAH emission as a star formation tracer as well as for modelling dust emission and radiative transfer.

scholarly journals IRAC Excess in Distant Star‐Forming Galaxies: Tentative Evidence for the 3.3 μm Polycyclic Aromatic Hydrocarbon Feature?

2008 ◽  
Vol 681 (1) ◽  
pp. 258-268 ◽  
Author(s):  
B. Magnelli ◽  
R. R. Chary ◽  
A. Pope ◽  
D. Elbaz ◽  
G. Morrison ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Star Forming ◽  
Distant Star ◽  
Polycyclic Aromatic ◽  
Tentative Evidence

Mid-infrared PAH emission from star-forming galaxies selected at 250 μm

2019 ◽  
Vol 15 (S341) ◽  
pp. 281-282
Author(s):  
Seong Jin Kim ◽  
Keyword(s):  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Physical Modeling ◽  
Wide Field ◽  
Mid Infrared ◽  
Star Forming ◽  
Polycyclic Aromatic ◽  
Data Points ◽  
Cold Dust ◽  
Strong Radiation

AbstractThe infrared (IR) galaxies detected at Herschel/SPIRE 250 μm band over the AKARI’s NEP-Wide field are various types of dusty star-forming (SF) galaxies ranging from quiescent to starbursts, having mid-IR polycyclic aromatic hydrocarbon (PAH) features near 8 μm. The measurements of the 8 μm luminosity (L8μm) along with the total infrared luminosity (LIR) based on the physical modeling of SEDs a take unique advantage of the continuous near- to mid-IR coverage, far-IR data points, and spectroscopically determined accurate redshifts. Our sample shows shortage of 8 μm luminosity compared to the total IR luminosity. This deficit gets severe in more luminous IR galaxies, suggesting PAH molecules in these galaxies are destroyed by a strong radiation field from SF regions, or the existence of a unexpectedly large amount of cold dust in the ISM that contributes to LIR.

1,1’-Biaceanthrylene and 2,2'-Biaceanthrylene: Models for Linking Larger Polycyclic Aromatic Hydrocarbons via Five-Membered Rings

2019 ◽  
Author(s):  
Yachu Du ◽  
Kyle Plunkett
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Electronic Properties ◽  
Aromatic Hydrocarbons ◽  
Model Systems ◽  
Redox Potentials ◽  
Dimer Model ◽  
Optical And Electronic Properties ◽  
Polycyclic Aromatic

We show that polycyclic aromatic hydrocarbon (PAH) chromophores that are linked between two five-membered rings can access planarized structures with reduced optical gaps and redox potentials. Two aceanthrylene chromophores were connected into dimer model systems with the chromophores either projected outward (2,2’-biaceanthrylene) or inward (1,1’-biaceanthrylene) and the optical and electronic properties were compared. Only the planar 2,2’-biaceanthrylene system showed significant reductions of the optical gaps (1 eV) and redox potentials in relation to the aceanthrylene monomer.<br>

1,1’-Biaceanthrylene and 2,2'-Biaceanthrylene: Models for Linking Larger Polycyclic Aromatic Hydrocarbons via Five-Membered Rings

2019 ◽  
Author(s):  
Yachu Du ◽  
Kyle Plunkett
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Electronic Properties ◽  
Aromatic Hydrocarbons ◽  
Model Systems ◽  
Redox Potentials ◽  
Dimer Model ◽  
Optical And Electronic Properties ◽  
Polycyclic Aromatic

We show that polycyclic aromatic hydrocarbon (PAH) chromophores that are linked between two five-membered rings can access planarized structures with reduced optical gaps and redox potentials. Two aceanthrylene chromophores were connected into dimer model systems with the chromophores either projected outward (2,2’-biaceanthrylene) or inward (1,1’-biaceanthrylene) and the optical and electronic properties were compared. Only the planar 2,2’-biaceanthrylene system showed significant reductions of the optical gaps (1 eV) and redox potentials in relation to the aceanthrylene monomer.<br>

Karakterisasi Komponen Aktif Asap Cair Cangkang Sawit Hasil Pemurnian

2016 ◽  
Vol 9 (1) ◽  
pp. 64-72
Author(s):  
Fauziati Fauziati ◽  
Eldha Sampepana
Keyword(s):  
Acetic Acid ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Activated Charcoal ◽  
Oil Refining ◽  
Gas Chromatography Mass Spectrometry ◽  
Antioxidant Compounds ◽  
Active Components ◽  
Liquid Smoke ◽  
Polycyclic Aromatic

Palm shell liquid smoke obtained by pyrolysis and redestilasi still produce a pungent smoke flavor and color of yellow to brownish yellow so that the necessary research purification of smoke that can be used as ingredients other than preservatives, such as antiseptic hand wash. The research objective is to reduce the stinging liquid smoke aroma, color is tawny and to identify the characterization of the active components of liquid smoke shell oil refining results in Gas Chromatography Mass Spectrometry (GC-MS). The purification process of liquid smoke with redistilled at a temperature of 2000C and by adding 4.5% zeolite adsorbent made three (3) times the resulting liquid smoke of distillate and residue. Liquid smoke produced from distillate and residue are added activated charcoal as much as 9%, 10.5% and 12%, then stirred with a shaker subsequently allowed to stand for 6 days and 10 days The results of the study showed that liquid smoke purification results of the residue by the addition of activated charcoal as 12% and the time saved for 10 days (A2B2C3) gives flavor and color by 1.94 of 1.84 is odorless, yellowish white color and clarity. While the characteristics of the active components of purification results are predominantly acetic acid and phenol compounds of residues that serve as preservatives, antibacterial and antioxidant compounds while PAH (Polycyclic Aromatic Hydrocarbon), namely tar, benzoperen, gualakol and siringoll (aroma causes) undetectedABSTRAKAsap cair cangkang sawit yang diperoleh melalui proses pirolisis dan redestilasi masih menghasilkan aroma asap menyengat dan warna kuning hingga kuning kecoklatan sehingga diperlukan penelitian pemurnian asap yang dapat digunakan sebagai bahan lain selain pengawet, seperti antiseptik pencuci tangan. Tujuan penelitian adalah  untuk mengurangi aroma asap cair yang menyengat, warna yang masih kuning kecoklatan dan untuk  mengidentifikasi karakterisasi komponen aktif asap cair cangkang sawit hasil pemurnian secara Kromatografi Gas Spektrometri Massa (GC-MS). Proses  pemurnian asap cair dengan  redistilasi pada suhu 2000C dan dengan menambahkan adsorben zeolit 4,5% yang dilakukan sebanyak 3 (tiga) kali  dihasilkan asap cair dari Destilat dan Residu . Asap cair  yang dihasilkan dari destilat dan residu ditambahkan arang aktif sebanyak 9%,10,5% dan 12%  kemudian diaduk dengan shaker selanjutnya didiamkan selama 6 hari dan 10 hari .Hasil penelitian menunjukkan bahwa asap cair hasil pemurnian dari residu dengan penambahan arang aktif sebanyak 12% dan waktu simpan selama 10 hari ( A2B2C3 ) memberikan aroma sebesar 1,94 dan warna sebesar 1,84 adalah tidak berbau ,  warna putih kekuningan dan jernih . Sedangkan  karakteristik  komponen aktif hasil pemurnian yang paling dominan  adalah  senyawa acetic acid dan phenol  dari residu yang berfungsi sebagai bahan pengawet, antibakteri dan antioksidan sedangkan senyawa PAH (Polycyclic Aromatic Hydrocarbon) yaitu tar, benzoperen,  gualakol  dan siringoll ( penyebab aroma ) tidak terdeteksi . Kata kunci : asap cair, cangkang sawit, komponen aktif, pemurnian, redestilasi 

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