Rotational Dynamics and Star Formation in the Nearby Dwarf Galaxy NGC 5238

Cannon, John; McNichols, Andrew; Teich, Yaron; Ball, Catherine; Banovetz, John; Brock, Annika; Eisner, Brian A.; Fitzgibbon, Kathleen; Miazzo, Masao; Nizami, Asra; Ruvolo, Elizabeth; Singer, Quinton

doi:10.3847/0004-6256/152/6/202

Cited by 8 publications

(5 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…NGC5238: Classified as SABdm in NED, this galaxy belongs to the Canes Venatici I group. From the HI perspective, Cannon et al (2016) found that the HI disk is asymmetric in the outer regions, and the HI surface density maximum is not coincident with the central optical peak, but rather is offset to the North-East by ∼ 300 pc. Our maps suggest that the iso-contours of the young population are also twisted with respect to the RGB ellipse.…”

Section: Sf Spatial Patternsmentioning

confidence: 99%

Star Formation Histories of the LEGUS Dwarf Galaxies. III. The Nonbursty Nature of 23 Star-forming Dwarf Galaxies*

Cignoni

Sacchi

Tosi

et al. 2019

ApJ

View full text Add to dashboard Cite

We derive the recent star formation histories of 23 active dwarf galaxies using HST observations from the Legacy Extragalactic UV Survey (LEGUS). We apply a color-magnitude diagram fitting technique using two independent sets of stellar models, PARSEC-COLIBRI and MIST. Despite the non-negligible recent activity, none of the 23 star forming dwarfs show enhancements in the last 100 Myr larger than three times the 100-Myr-average. The unweighted mean of the individual SFHs in the last 100 Myr is also consistent with a rather constant activity, irrespective of the atomic gas fraction. We confirm previous results that for dwarf galaxies the CMD-based average star formation rates (SFRs) are generally higher than the FUV-based SFR. For half of the sample, the 60-Myr-average CMD-based SFR is more than two times the FUV SFR. In contrast, we find remarkable agreement between the 10-Myr-average CMD-based SFR and the Hα-based SFR. Finally, using core helium burning stars of intermediate mass we study the pattern of star formation spatial progression over the past 60 Myr, and speculate on the possible triggers and connections of the star formation activity with the environment in which these galaxies live. Approximately half of our galaxies show spatial progression of star formation in the last 60 Myr, and/or very recent diffuse and off-center activity compared to RGB stars.

show abstract

Section: Sf Spatial Patternsmentioning

confidence: 99%

Star Formation Histories of the LEGUS Dwarf Galaxies. III. The Nonbursty Nature of 23 Star-forming Dwarf Galaxies*

Cignoni

Sacchi

Tosi

et al. 2019

ApJ

View full text Add to dashboard Cite

show abstract

“…In the first line of investigation we apply the spatially resolved position-velocity analysis developed in Cannon et al (2011b) and employed in McNichols et al (2016) and Cannon et al (2016). This technique allows us to estimate the projected rotation velocity of a source when its kinematics are not well described by a simple tilted ring.…”

Section: Spatially Resolved Position-velocity Analysismentioning

confidence: 99%

The Enigmatic (Almost) Dark Galaxy Coma P: The Atomic Interstellar Medium

Ball

Cannon

Adams

et al. 2018

Self Cite

View full text Add to dashboard Cite

We present new high-resolution H I spectral line imaging of Coma P, the brightest H I source in the system HI 1232 +20. This galaxy with extremely low surface brightness was first identified in the ALFALFA survey as an "(Almost) Dark" object: a clearly extragalactic H I source with no obvious optical counterpart in existing optical survey data (although faint ultraviolet emission was detected in archival GALEX imaging). Using a combination of data from the Westerbork Synthesis Radio Telescope and the Karl G. Jansky Very Large Array, we investigate the H I morphology and kinematics at a variety of physical scales. The H I morphology is irregular, reaching only moderate maxima in mass surface density (peak M 10 H I s~ pc −2 ). Gas of lower surface brightness extends to large radial distances, with the H I diameter measured at 4.0±0.2 kpc inside the M 1  pc −2 level. We quantify the relationships between mass surface density of H I gas and star formation on timescales of ∼100-200 Myr as traced by GALEX far-ultraviolet emission. While Coma P has regions of dense H I gas reaching the N 10 I I scaling relation. It is either too large for its H I mass, has too low an H I mass for its H I size, or the two H I components artificially extend its H I size. Coma P lies within the empirical scatter at the faint end of the baryonic Tully-Fisher relation, although the complexity of the H I dynamics complicates the interpretation. Along with its large ratio of H I to stellar mass, the collective H I characteristics of Coma P make it unusual among known galaxies in the nearby universe.

show abstract

“…For consistency with the results presented in Teich et al (2016) and Cannon et al (2016), we use both values of inclination for each galaxy in the discussion that follows. The lower inclinations dervied using the HST images compared to those using the ground-based images can be attributed to the different surface brightness sensitivities of the two sets of images, and also in part to the differences in the methods applied to excise foreground and background objects.…”

Section: Discussionmentioning

confidence: 98%

First Characterization of the Neutral ISM in Two Local Volume Dwarf Galaxies

Bralts-Kelly

Bulatek

Chinski

et al. 2017

ApJL

Self Cite

View full text Add to dashboard Cite

We present the first HI spectral line images of the nearby, star-forming dwarf galaxies UGC 11411 and UGC 8245, acquired as part of the "Observing for University Classes" program with the Karl G. Jansky Very Large Array (VLA a ). These low-resolution images localize the HI gas and reveal the bulk kinematics of each system. Comparing with HST broadband and ground-based Hα imaging, we find that the ongoing star formation in each galaxy is associated with the highest HI mass surface density regions. UGC 8245 has a much lower current star formation rate than UGC 11411, which harbors very high surface brightness Hα emission in the inner disk and diffuse, lower surface brightness nebular gas that extends well beyond the stellar disk as traced by HST. We measure the dynamical masses of each galaxy and find that the halo of UGC 11411 is more than an order of magnitude more massive than the halo of UGC 8245, even though the HI and stellar masses of the sources are similar. We show that UGC 8245 shares similar physical properties with other well-studied low-mass galaxies, while UGC 11411 is more highly dark matter dominated. Both systems have negative peculiar velocities that are associated with a coherent flow of nearby galaxies at high supergalactic latitude.

show abstract

Rotational Dynamics and Star Formation in the Nearby Dwarf Galaxy NGC 5238

Cited by 8 publications

References 49 publications

Star Formation Histories of the LEGUS Dwarf Galaxies. III. The Nonbursty Nature of 23 Star-forming Dwarf Galaxies*

Star Formation Histories of the LEGUS Dwarf Galaxies. III. The Nonbursty Nature of 23 Star-forming Dwarf Galaxies*

The Enigmatic (Almost) Dark Galaxy Coma P: The Atomic Interstellar Medium

First Characterization of the Neutral ISM in Two Local Volume Dwarf Galaxies

Contact Info

Product

Resources

About