CO Observations of 2nd quadrant IRAS Sources

Braine, J.; Dupraz, C.; Casoli, F.; Combes, F.; Gérin, M.

doi:10.1007/bfb0119464

Cited by 102 publications

(173 citation statements)

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“…All of these galaxies are from Nishiyama & Nakai (2001) and Braine et al (1993) for the NRO 45 m and IRAM 30 m measurements, respectively. NGC 3810 has a starbursting nucleus, and its I CO at a single beam away from its nucleus drops to nearly half the value found by Nishiyama & Nakai (2001).…”

Section: Other Data and Consistencymentioning

confidence: 99%

“…The observing coordinates for NGC 7331 differ by 14 00 . Since the coordinates in Braine et al (1993) are offset from the true center, the difference in I CO may reflect the central CO hole, which explains the smaller CO intensity in Nishiyama & Nakai (2001). Nevertheless, it is important to bear in mind that when comparing CO intensities from the different telescopes, an error of typically a factor of 2 may in fact be involved.…”

Section: Other Data and Consistencymentioning

confidence: 99%

“…In the following sections, we either use the CO intensity alone (without correcting for inclination) or use intensity ratios in different beam sizes to cancel any effects from inclinations. Figure 8 shows the number distribution of the ratio of molecular gas surface mass density in the central 1 kpc to the central Young et al (1995) unless otherwise noted; values marked with an asterisk are from Böker et al (2003), values marked with two asterisks are from Braine et al (1993), and values marked with three asterisks are from Liu & Graham (2001). Values have been converted using H 0 ¼ 75 km s À1 Mpc À1 .…”

Section: Other Data and Consistencymentioning

confidence: 99%

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Molecular Gas Distribution in Barred and Nonbarred Galaxies along the Hubble Sequence

Komugi

Sofue

Kohno

et al. 2008

ASTROPHYS J SUPPL S

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We present results from a survey of 12 CO (J ¼ 1Y0) spectra obtained for the central regions of 68 nearby galaxies at an angular resolution of 16 00 using the Nobeyama Radio Observatory 45 m telescope, aimed at characterizing the properties of star-forming molecular gas. Combined with observations of similar resolution in the literature, the compiled sample set of 166 galaxies span a wide range of galactic properties. NGC 4380, which was previously undetected in CO, was detected. This initial paper of a series will focus on the data and the gaseous properties of the samples, and particularly on the degree of central concentration of molecular gas in a range of morphological types, from early (S0/Sa) to late (Sd /Sm) galaxies with and without bars. The degree of molecular central concentration in the central kiloparsec, compared with the central several kiloparsecs of galaxies, is found to vary smoothly with Hubble type, so that early-type galaxies show larger central concentration. The comparison of barred and nonbarred galaxies within early-and late-type galaxies suggest that difference in Hubble type, representing the effect of bulges, is the more important factor in concentrating gas into the central regions than bars.

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Section: Other Data and Consistencymentioning

confidence: 99%

Section: Other Data and Consistencymentioning

confidence: 99%

Section: Other Data and Consistencymentioning

confidence: 99%

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Molecular Gas Distribution in Barred and Nonbarred Galaxies along the Hubble Sequence

Komugi

Sofue

Kohno

et al. 2008

ASTROPHYS J SUPPL S

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“…In our case such a physical region at the distance of the sources corresponds to an aperture that ranges from 0.5 to 4 kpc for the CO(1-0) transition. CO interferometric observations show that the molecular gas in ETGs is centrally concentrated in the central kiloparsecs (e.g., Braine et al 1993;Boselli et al 2002;Böker et al 2003;Komugi et al 2008;Davis et al 2013). Recently by comparing the CO fluxes recovered from 30 m spectra and from full interferometric maps (from CARMA) for a sample of local ETGs, Alatalo et al (2013) found that up to half of the molecular mass of a source (at a similar distance to our sample) measured with the 30 m telescope can be missed.…”

Section: Co Emission and H 2 Mass Estimationmentioning

confidence: 54%

Molecular gas and nuclear activity in early-type galaxies: any link with radio loudness?

Baldi

Giroletti

Capetti

et al. 2015

A&A

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Aims. We want to study the amount of molecular gas in a sample of nearby early-type galaxies (ETGs) that host low-luminosity active galactic nuclei (AGN). We look for possible differences between the radio-loud (RL) and radio-quiet (RQ) AGN. Methods. We observed the CO(1-0) and CO(2-1) spectral lines with the IRAM 30 m and NRO 45 m telescopes for eight galaxies. They belong to a large sample of 37 local ETGs that host both RQ and RL AGN. We gather data from the literature for the entire sample. Results. We report the new detection of CO(1-0) emission in four galaxies (UGC 0968, UGC 5617, UGC 6946, and UGC 8355) and CO(2-1) emission in two of them (UGC 0968 and UGC 5617). The CO(2-1)/CO(1-0) ratio in these sources is ∼0.7 ± 0.2. Considering both the new observations and the literature, the detection rate of CO in our sample is 55± 9%, with no statistically significant difference between the hosts of RL and RQ AGNs. For all the detected galaxies we converted the CO luminosities into the molecular masses, M H 2 , which range from 10 6.5 to 10 8.5 M , without any statistically significant differences between RL and RQ galaxies. This suggests that the amount of molecular gas does not likely set the radio loudness of the AGN. Furthermore, despite the low statistical significance, the presence of a weak trend between the H 2 mass with various tracers of nuclear activity (mainly [O III] emission line nuclear power) cannot be excluded.

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“…This corresponds to a molecular gas mass of 4.0 × 10 8 M and 1.0 × 10 8 M , respectively. These values are corrected for the helium abundance, and an assumed, constant, I CO(2−1) /I CO(1−0) line ratio of 0.89 (Braine et al 1993) was used. Similar ratios are found for the central regions of other nearby galaxies, (Koda et al 2012;Sandstrom et al 2012).…”

Section: Co(2−1) Morphologymentioning

confidence: 99%

Explaining two circumnuclear star forming rings in NGC 5248

Laan

Schinnerer

Emsellem

et al. 2013

A&A

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The distribution of gas in the central kiloparsec of a galaxy has a dynamically rapid evolution. Nonaxisymmetries in the gravitational potential of the galactic disk, such as a large scale stellar bar or spiral, can lead to significant radial motion of gaseous material from larger radii to the central region. The large influx of gas and the subsequent star formation keep the central region constantly changing. However, the ability of gas to reach the nucleus proper to fuel an AGN phase is not guaranteed. Gas inflow can be halted at a circumnuclear star forming ring several hundred parsec away. The nearby galaxy NGC 5248 is especially interesting in this sense since it is said to host 2 circumnuclear star forming rings at 100 pc and 370 pc from its quiescent nucleus. Here we present new subarcsecond PdBI+30 m CO(2−1) emission line observations of the central region. For the first time the molecular gas distribution at the smallest stellar ring is resolved into a gas ring, consistent with the presence of a quiescent nucleus. However, the molecular gas shows no ring structure at the larger ring. We combine analyses of the gaseous and stellar content in the central kiloparsec of this galaxy to understand the gas distribution and dynamics of this star forming central region. We discuss the probability of two scenarios leading to the current observations, given our full understanding of this system, and discuss whether there are really two circumnuclear star forming rings in this galaxy.

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CO Observations of 2nd quadrant IRAS Sources

Cited by 102 publications

References 1 publication

Molecular Gas Distribution in Barred and Nonbarred Galaxies along the Hubble Sequence

Molecular Gas Distribution in Barred and Nonbarred Galaxies along the Hubble Sequence

Molecular gas and nuclear activity in early-type galaxies: any link with radio loudness?

Explaining two circumnuclear star forming rings in NGC 5248

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