Multi-Wavelength Studies of Spectacular Ram-Pressure Stripping of a Galaxy. Ii. Star Formation in the Tail

Yagi, Masafumi; Gu, Liyi; Fujita, Yutaka; Nakazawa, K.; Akahori, Takuya; Hattori, Takashi; Yoshida, Michitoshi; Makishima, Kazuo

doi:10.1088/0004-637x/778/2/91

Cited by 31 publications

(40 citation statements)

References 106 publications

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“…In all galaxies where tails have been observed, the ionized gas has a structured distribution, with high density clumps of condensed material that is often associated with star-forming regions, otherwise extended in filamentary structures (Yagi et al 2007(Yagi et al , 2010(Yagi et al , 2013. Similar structures are also present in hydrodynamic simulations (e.g.…”

Section: Narrow-band Imagingmentioning

confidence: 64%

Spectacular tails of ionized gas in the Virgo cluster galaxy NGC 4569

Boselli

Cuillandre

Fossati

et al. 2016

A&A

132

169

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Using MegaCam at the CFHT, we obtained a deep narrow band Hα+ [NII] wide-field image of NGC 4569 (M90), the brightest late-type galaxy in the Virgo cluster. The image reveals the presence of long tails of diffuse ionized gas, without any associated stellar component extending from the disc of the galaxy up to 80 kpc (projected distance) and with a typical surface brightness of a few 10 −18 erg s −1 cm −2 arcsec −2 . These features provide direct evidence that NGC 4569 is undergoing a ram-presure stripping event. The image also shows a prominent 8 kpc spur of ionized gas that is associated with the nucleus that spectroscopic data identify as an outflow. With some assumptions on the 3D distribution of the gas, we use the Hα surface brightness of these extended low-surface brightness features to derive the density and the mass of the gas that has been stripped during the interaction of the galaxy with the intracluster medium. The comparison with ad hoc chemo-spectrophotometric models of galaxy evolution indicates that the mass of the Hα emitting gas in the tail is a large fraction of that of the cold phase that has been stripped from the disc, suggesting that the gas is ionized within the tail during the stripping process. The lack of star-forming regions suggests that mechanisms other than photoionization are responsible for the excitation of the gas (shocks, heat conduction, magneto hydrodynamic waves). This analysis indicates that ram pressure stripping is efficient in massive (M star 10 10.5 M ) galaxies located in intermediate-mass ( 10 14 M ) clusters under formation. It also shows that the mass of gas expelled by the nuclear outflow is only ∼1% than that removed during the ram pressure stripping event. Together these results indicate that ram pressure stripping, rather than starvation through nuclear feedback, can be the dominant mechanism that is responsible for the quenching of the star formation activity of galaxies in high density environments.Key words. galaxies: individual: NGC 4569 -galaxies: clusters: general -galaxies: clusters: individual: Virgo -galaxies: evolutiongalaxies: interactions -galaxies: ISM Based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canadian-French-Hawaii Telescope (CFHT) which is operated by the

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Section: Narrow-band Imagingmentioning

confidence: 64%

Spectacular tails of ionized gas in the Virgo cluster galaxy NGC 4569

Boselli

Cuillandre

Fossati

et al. 2016

A&A

132

169

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“…Rather surprisingly, regions of young star formation have been revealed in some of the tails, either in Hα or UV (Kenney & Koopmann 1999;Cortese et al 2006;Sun et al 2007;Yoshida et al 2008;Smith et al 2010;Hester et al 2010;Yagi et al 2013;Ebeling et al 2014). This indicates that while ram pressure generally suppresses star formation in the disks, it may induce new star formation in the stripped medium.…”

Section: Introductionmentioning

confidence: 99%

Molecular Gas Dominated 50 kpc Ram Pressure Stripped Tail of the Coma Galaxy D100^*

Jáchym

Sun

Kenney

et al. 2017

ApJ

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119

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We have discovered large amounts of molecular gas, as traced by CO emission, in the ram pressure stripped gas tail of the Coma cluster galaxy D100 (GMP 2910), out to large distances of about 50 kpc. D100 has a 60 kpc long, strikingly narrow tail which is bright in X-rays and Hα. Our observations with the IRAM 30m telescope reveal in total ∼ 10 9 M ⊙ of H 2 (assuming the standard CO-to-H 2 conversion) in several regions along the tail, thus indicating that molecular gas may dominate its mass. Along the tail we measure a smooth gradient in the radial velocity of the CO emission that is offset to lower values from the more diffuse Hα gas velocities. Such a dynamic separation of phases may be due to their differential acceleration by ram pressure. D100 is likely being stripped at a high orbital velocity 2200 km s −1 by (nearly) peak ram pressure. Combined effects of ICM viscosity and magnetic fields may be important for the evolution of the stripped ISM. We propose D100 has reached a continuous mode of stripping of dense gas remaining in its nuclear region. D100 is the second known case of an abundant molecular stripped-gas tail, suggesting that conditions in the ICM at the centers of galaxy clusters may be favorable for molecularization. From comparison with other galaxies, we find there is a good correlation between the CO flux and the Hα surface brightness in ram pressure stripped gas tails, over ∼ 2 dex.

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“…Detections of young star forming regions with solar metallicity is not uncommon: about ten star-forming regions are reported in the literature. Recently Yagi et al (2013) also detected four regions in the Virgo cluster. The detection of young star forming regions with a metallicity (12 + log(O/H)) larger than 8.3 indicate that merger events may be responsible for enriching the intergalactic medium with metals by dispersing pre-enriched gas from the progenitor galaxies, which is also observed in the galaxy NGC 92 by Torres-Flores et al (2014).…”

Section: Metallicitymentioning

confidence: 96%

“…With the detections of these intergalactic systems, we can analyze the probability to form stellar systems in environments where the gas density, HI ∼ 10 19 cm −2 , is very low. In recent years, various authors reported intergalactic objects in interacting systems with gas tails, such as tidal dwarf galaxies (e.g., Duc & Mirabel 1998;Duc et al 2000;Mendes de Oliveira et al 2001;Hibbard et al 2001;de Mello et al 2012;Lee-Waddell et al 2012) and intergalactic HII regions (e.g., Gerhard et al 2002;Ryan-Weber et al 2004;Mendes de Oliveira et al 2004;Arrigoni Battaia et al 2012;Torres-Flores et al 2012;de Mello et al 2012;Yagi et al 2013).…”

Section: Introductionmentioning

confidence: 99%

“…This is commonly observed in pairs or in close interacting galaxies, mainly in the systems, which contain disturbed HI features. Recently, many efforts have been devoted to several systems in the local universe to understand the physical conditions that lead to the formation of new stars and to determine whether these are responsible for polluting the intergalactic medium with metalenriched gas (e.g., Mendes de Oliveira et al 2004); Ryan-Weber et al (2004); Bournaud et al (2004);de Mello et al (2012); Torres-Flores et al (2012); Arrigoni Battaia et al (2012); Yagi et al (2013). These are important points, given that many studies (i.e., Songaila 2001;Pettini et al 2003;Becker et al 2006); Ryan-Weber et al (2006; Simcoe et al (2011);Díaz et al (2011);D'Odorico et al (2013) showed that the intergalactic medium at a redshift of at least 6 is not a pristine remnant of the Big Bang, but rather it contains significant quantities of metals.…”

Section: Introductionmentioning

confidence: 99%

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A census of Hαemitters in the intergalactic medium of the NGC 2865 system

Urrutia-Viscarra

Arnaboldi

Oliveira

et al. 2014

A&A

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Tidal debris, which are rich in HI gas and formed in interacting and merging systems, are suitable laboratories to study star formation outside galaxies. Recently, several such systems were observed, which contained many young star forming regions outside the galaxies. In previous works, we have studied young star forming regions outside galaxies in different systems with optical and/or gaseous tidal debris, in order to understand how often they occur and in which type of environments. In this paper, we searched for star forming regions around the galaxy NGC 2865, a shell galaxy that is circled by a ring of HI with a total mass of 1.2×10 9 M . Using the multi-slit imaging spectroscopy technique with the Gemini telescope, we detected all Hα emitting sources in the surroundings of the galaxy NGC 2865, down to a flux limit of 10 −18 erg cm −2 s −1 Å −1 . With the spectra information and the near and far-ultraviolet flux, we characterize the star formation rates, masses, ages, and metallicities for these HII regions. In total, we found 26 emission-line sources in a 60 × 60 Kpc field centered over the southeastern tail of the HI gas present around the galaxy NGC 2865. Out of the 26 Hα emitters, 19 are in the satellite galaxy FGCE 0745, and seven are intergalactic HII regions scattered over the south tail of the HI gas around NGC 2865. We found that the intergalactic HII regions are young (<200 Myr) with stellar masses in the range 4 × 10 3 M to 17 × 10 6 M . These are found in a region of low HI gas density, where the probability of forming stars is expected to be low. For one of the intergalactic HII regions, we estimated a solar oxygen abundance of 12 + log(O/H) ∼ 8.7. We also were able to estimate the metallicity for the satellite galaxy FGCE 0745 to be 12 + log(O/H) ∼ 8.0. Given these physical parameters, the intergalactic HII regions are consistent with young star forming regions (or clusters), which are born in situ outside the NGC 2865 galaxy from a pre-enriched gas removed from the host galaxies in a merger event. The relevance of these observations is discussed.

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Multi-Wavelength Studies of Spectacular Ram-Pressure Stripping of a Galaxy. Ii. Star Formation in the Tail

Cited by 31 publications

References 106 publications

Spectacular tails of ionized gas in the Virgo cluster galaxy NGC 4569

Spectacular tails of ionized gas in the Virgo cluster galaxy NGC 4569

Molecular Gas Dominated 50 kpc Ram Pressure Stripped Tail of the Coma Galaxy D100^*

A census of Hαemitters in the intergalactic medium of the NGC 2865 system

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Multi-Wavelength Studies of Spectacular Ram-Pressure Stripping of a Galaxy. Ii. Star Formation in the Tail

Cited by 31 publications

References 106 publications

Spectacular tails of ionized gas in the Virgo cluster galaxy NGC 4569

Spectacular tails of ionized gas in the Virgo cluster galaxy NGC 4569

Molecular Gas Dominated 50 kpc Ram Pressure Stripped Tail of the Coma Galaxy D100*

A census of Hαemitters in the intergalactic medium of the NGC 2865 system

Contact Info

Product

Resources

About

Molecular Gas Dominated 50 kpc Ram Pressure Stripped Tail of the Coma Galaxy D100^*