Detection of unidentified infrared bands in a H<i>α</i>filament in the dwarf galaxy NGC 1569 with AKARI

Onaka, Takashi; Matsumoto, Hiroko; Sakon, Itsuki; Kaneda, Hidehiro

doi:10.1051/0004-6361/200913770

Cited by 19 publications

(26 citation statements)

References 84 publications

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“…Our result on the detection of the 3.3 μm feature from the halo spectra unambiguously confirms the presence of very small PAHs in the galactic superwind of M 82. With AKARI near-to mid-IR spectroscopy, Onaka et al (2010) also detected the PAH features including the 3.3 μm feature in the filamentary outflow of the starburst dwarf galaxy NGC 1569. Thus, to our knowledge, this is the second clear detection of the PAH 3.3 μm feature in galactic superwind far outside a galactic disk.…”

Section: Discussionmentioning

confidence: 95%

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AKARI near-infrared spectroscopy of the aromatic and aliphatic hydrocarbon emission features in the galactic superwind of M 82

Yamagishi

Kaneda

Ishihara

et al. 2012

A&A

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Aims. We investigate the properties of hydrocarbon grains in the galactic superwind of M 82. Methods. With AKARI, we performed near-infrared (2.5-4.5 μm) spectroscopic observations of 34 regions in M 82 including its northern and southern halos. Results. Many of the spectra show strong emission at 3.3 μm caused by polycyclic aromatic hydrocarbons (PAHs) and relatively weak features at 3.4-3.6 μm caused by aliphatic hydrocarbons. In particular, we clearly detect the PAH 3.3 μm emission and the 3.4-3.6 μm features in halo regions, which are located at a distance of 2 kpc away from the galactic center. We find that the ratios of the 3.4-3.6 μm features to the 3.3 μm feature intensity significantly increase with distance from the galactic center, while the ratios of the 3.3 μm feature to the AKARI 7 μm band intensity do not. Conclusions. Our results clearly confirm the presence of small PAHs even in the harsh environment of the halo of M 82. The results also reveal that the aliphatic hydrocarbons emitting the 3.4-3.6 μm features are unusually abundant in the halo, suggesting that small carbonaceous grains are produced by shattering of larger grains in the galactic superwind.

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Section: Discussionmentioning

confidence: 95%

“…Thus, to our knowledge, this is the second clear detection of the PAH 3.3 μm feature in galactic superwind far outside a galactic disk. Onaka et al (2010) suggested that the PAHs in the filament of NGC 1569 might be produced from the fragmentation of large carbonaceous grains in shocks. Our halo spectra in Fig.…”

Section: Discussionmentioning

confidence: 99%

AKARI near-infrared spectroscopy of the aromatic and aliphatic hydrocarbon emission features in the galactic superwind of M 82

Yamagishi

Kaneda

Ishihara

et al. 2012

A&A

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“…The PAH features in galaxy halos seem to have a lower 7.7 µm to 11.3 µm band ratio than that in galactic disks (Irwin & Madden 2006;Galliano et al 2008b). A similar small ratio is also indicated in the interarm region as well as in a filamentary structure associated with the galactic wind (Onaka et al 2010a). The small ratio may be attributed to processing of the band carriers in these tenuous regions or could be related to their formation process.…”

Section: Introductionmentioning

confidence: 62%

“…They may be formed in carbon-rich stars (Galliano et al 2008a;Paradis et al 2008) or in dense clouds (Herbst 1991;Sandstrom et al 2010). Recent observations withAKARI and SOFIA suggest that PAHs are also formed by fragmentation of large carbonaceous grains in shocks associated with a supernova, a galactic wind, or an outflow from a planetary nebula (Onaka et al 2010a;Seok et al 2012;Lau et al 2016).…”

Section: Introductionmentioning

confidence: 99%

Near-infrared to Mid-infrared Observations of Galaxy Mergers: NGC 2782 and NGC 7727

Onaka

Nakamura

Sakon

et al. 2018

ApJ

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We present the results of near-to mid-infrared (NIR to MIR) imaging and NIR spectroscopic observations of two galaxy mergers, NGC 2782 (Arp 215) and NGC 7727 (Arp 222), with the Infrared Camera on board AKARI. NGC 2782 shows extended MIR emission in the eastern side of the galaxy, which corresponds to the eastern tidal tail seen in the H I 21 cm map, while NGC 7727 shows extended MIR emission in the north of the galaxy, which is similar to the plumes seen in the residual image at the K-band after subtracting a galaxy model. Both extended structures are thought to have formed associated with their merger events. They show excess emission at 7-15 µm, which can be attributed to emission from polycyclic aromatic hydrocarbons (PAHs), while the observed spectral energy distributions decline longward of 24 µm, suggesting that very small grains (VSGs) are deficient. These characteristics of the observed MIR spectral energy distribution may be explained if PAHs are formed by fragmentation of VSGs during merger events. The star formation rate is estimated from the MIR PAH emission in the eastern tail region of NGC 2782 and it is in fair agreement with those estimated from Hα and [C II] 158 µm. MIR observations are efficient for the study of dust processing and structures formed during merger events.

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“…For example, we detected galactic outflows of polycyclic aromatic hydrocarbons (PAHs) in the halos of M 82 and NGC 1569 (Yamagishi et al 2012;Onaka et al 2010). We found large variations in the intensity of the aliphatic emission relative to aromatic emission in the galactic superwind regions of M 82 (Yamagishi et al 2012) and the inner galactic bar of NGC 1097 (Kondo et al 2012), indicating systematic changes in the properties of hydrocarbon grains possibly due to large-scale shocks.…”

Section: Uniqueness Of Akari Datamentioning

confidence: 88%

Properties of Dust in Various Environments of Nearby Galaxies

Kaneda¹,

Kokusho²,

Yamada³

et al. 2017

Publications of The Korean Astronomical Society

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We have performed systematic studies of the properties of dust in various environments of nearby galaxies with AKARI. The unique capabilities of AKARI, such as near-infrared (near-IR) spectroscopy combined with all-sky coverage in the mid-and far-IR, enable us to study processing of dust, particularly carbonaceous grains includings polycyclic aromatic hydrocarbons (PAHs), for unbiased samples of nearby galaxies. In this paper, we first review our recent results on individual galaxies, highlighting the uniqueness of AKARI data for studies of nearby galaxies. Then we present results of our systematic studies on nearby starburst and early-type galaxies. From the former study based on the near-IR spectroscopy and mid-IR all-sky survey data, we find that the properties of PAHs change systematically from IR galaxies to ultraluminous IR galaxies, depending on the IR luminosity of a galaxy or galaxy population. From the latter study based on the mid-and far-IR all-sky survey data, we find that there is a global correlation between the amounts of dust and old stars in early-type galaxies, giving an observational constraint on the origin of the dust.Key words: Infrared: ISM -Infrared: galaxies -ISM: dust, extinction -Galaxies: ISM UNIQUENESS OF AKARI DATAFor studies of nearby galaxies, AKARI has provided us with unique datasets. All-sky mid-and far-infrared (far-IR) surveys at wavelengths of 9, 18, 65, 90, 140 and 160 µm are very powerful to detect IR emission widely extended around galaxies and even into intergalactic regions. Figure 1 shows the mid-and far-IR images of the edge-on starburst galaxy, NGC 253, obtained by the all-sky surveys. They clearly exhibit IR emission widely extended to the galactic halo regions. The AKARI surveys also enable us to investigate mid-to far-IR spectral energy distributions (SEDs) for unbiased samples of nearby galaxies all over the sky.Near-IR spectroscopy for a wavelength range of 2.5−5 µm offers valuable information on the interstellar media in galaxies with dust emission/absorption bands due to http://pkas.kas.org hydrocarbon particles and ices as well as hydrogen recombination emission lines. For example, we detected galactic outflows of polycyclic aromatic hydrocarbons (PAHs) in the halos of M 82 and NGC 1569 (Yamagishi et al. 2012;Onaka et al. 2010). We found large variations in the intensity of the aliphatic emission relative to aromatic emission in the galactic superwind regions of M 82 (Yamagishi et al. 2012) and the inner galactic bar of NGC 1097 (Kondo et al. 2012), indicating systematic changes in the properties of hydrocarbon grains possibly due to large-scale shocks. We also revealed spatial variations of relative abundances of interstellar H 2 O and CO 2 ices in NGC 253 and M 82, and found that they depend on the hardness of interstellar radiation field, i.e., massive star-forming activity Yamagishi et al. 2013).Wide dynamic ranges of signal detection are also im-135

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Detection of unidentified infrared bands in a Hαfilament in the dwarf galaxy NGC 1569 with AKARI

Cited by 19 publications

References 84 publications

AKARI near-infrared spectroscopy of the aromatic and aliphatic hydrocarbon emission features in the galactic superwind of M 82

AKARI near-infrared spectroscopy of the aromatic and aliphatic hydrocarbon emission features in the galactic superwind of M 82

Near-infrared to Mid-infrared Observations of Galaxy Mergers: NGC 2782 and NGC 7727

Properties of Dust in Various Environments of Nearby Galaxies

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