TWO LOCAL VOLUME DWARF GALAXIES DISCOVERED IN 21 cm EMISSION: PISCES A AND B

Tollerud, Erik; Geha, Marla; Grcevich, Jana; Putman, Mary E.; Stern, Daniel

doi:10.1088/2041-8205/798/1/l21

Cited by 40 publications

(64 citation statements)

References 34 publications

(34 reference statements)

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“…Therefore, the disparity between dark gas-rich galaxies (without clear stellar counterparts at present, e.g. Tollerud et al 2015), and the paucity of gas detected near the stellar overdensities identified by K15 and B15 , can be traced to the highy eccentric/energetic trajetory of the Magellanic Clouds/Group which penetrates some of the densest regions of the Galactic hot halo.…”

Section: Discussionmentioning

confidence: 99%

Local ultra faint dwarves as a product of Galactic processing during a Magellanic group infall

Yozin

Bekki

2015

Mon. Not. R. Astron. Soc.

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The recent discoveries of ultra-faint dwarf (UFD) galaxies in the vicinity of the Magellanic system supports the expectation from cosmological models that such faint objects exist and are numerous. By developing a mass model of the Local Group and backwards integrating the Magellanic Clouds' present kinematics, we find that the locations of these UFDs are consistent with those predicted if previously associated with the Large MC as part of a loose association. We further demonstrate how these satellites are likely to have been processed by the Galactic hot halo upon accretion, with the implication that ongoing detections of extremely gas-rich objects on the periphery of the Galaxy and without clear stellar counterparts are analogous to the progenitors of the gas-deficient UFDs. Our model allows us predict the locations of other putative Magellanic satellites, and propose how their distribution/kinematics provide a novel constraint on the dynamical properties of the Galaxy. We also predict that the stripped metal-poor H I, previously associated with these UFDs, lies coincident with but distinguishable from the extensive Magellanic Stream.

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Section: Discussionmentioning

confidence: 99%

Local ultra faint dwarves as a product of Galactic processing during a Magellanic group infall

Yozin

Bekki

2015

Mon. Not. R. Astron. Soc.

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“…using HI surveys, Tollerud et al 2015). In this Section we explore to what degree the sample size affects the constraints on our model parameters.…”

Section: Model Uncertainties and Sample Sizementioning

confidence: 99%

What galaxy masses perturb the local cosmic expansion?

Peñarrubia

Fattahi

2017

Monthly Notices of the Royal Astronomical Society

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We use 12 cosmological N-body simulations of Local Group systems (the APOSTLE models) to inspect the relation between the virial mass of the main haloes (M vir,1 and M vir,2 ), the mass derived from the relative motion of the halo pair (M tim ), and that inferred from the local Hubble flow (M lhf ). We show that within the Spherical Collapse Model (SCM), the correspondence between the three mass estimates is exact, i.e. M lhf = M tim = M vir,1 + M vir,2 . However, comparison with APOSTLE simulations reveals that, contrary to what the SCM states, a relatively large fraction of the mass that perturbs the local Hubble flow and drives the relative trajectory of the main galaxies is not contained within R vir , and that the amount of "extra-virial" mass tends to increase in galaxies with a slow accretion rate. In contrast, modelling the peculiar velocities around the Local Group returns an unbiased constraint on the virial mass ratio of the main galaxy pair. Adopting the outer halo profile found in N-body simulations, which scales as ρ ∼ R −4 at R R vir , indicates that the galaxy masses perturbing the local Hubble flow roughly correspond to the asymptotically-convergent (total) masses of the individual haloes. We show that estimates of M vir based on the dynamics of tracers at R R vir require a priori information on the internal matter distribution and the growth rate of the main galaxies, both of which are typically difficult to quantify.

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“…Most recently, so-called ultra-compact high velocity clouds (UCHVCs) of neutral hydrogen have been identified by the Galactic Arecibo L-Band Feed Array H I (GALFA-H I) and Arecibo Legacy Fast Arecibo L-Band Feed Array (ALFALFA) surveys (Saul et al 2012;Adams et al 2013, respectively) as potential sites of gas-bearing dark matter halos. Because the spatial distribution and physical properties of these UCHVCs are consistent with some being faint dwarf galaxies in the Local Volume (e.g., Giovanelli et al 2010;Adams et al 2013), several searches have been undertaken to characterize their optical properties (Bellazzini et al 2015a;Sand et al 2015;Tollerud et al 2015;Janesh et al 2015). These searches have yielded only a handful of plausible dwarf galaxy counterparts to the UCHVCs, while follow-up H I observations of others suggest that some may be "Dark" systems (e.g., Adams et al 2016).…”

Section: Introductionmentioning

confidence: 98%

Hubble Space Telescope Imaging of the Ultra-compact High Velocity Cloud AGC 226067: A Stripped Remnant in the Virgo Cluster

Sand

Seth

Crnojević

et al. 2017

ApJ

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We analyze the optical counterpart to the ultra-compact high velocity cloud AGC226067, utilizing imaging taken with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. The color-magnitude diagram of the main body of AGC226067 reveals an exclusively young stellar population, with an age of ∼7-50 Myr, and is consistent with a metallicity of [Fe/H]∼−0.3 as previous work has measured via H II region spectroscopy. Additionally, the color-magnitude diagram is consistent with a distance of D≈17 Mpc, suggesting an association with the Virgo cluster. A secondary stellar system located ∼1 6 (∼8 kpc) away in projection has a similar stellar population. The lack of an old red giant branch (5 Gyr) is contrasted with a serendipitously discovered Virgo dwarf in the ACS field of view (Dw J122147+132853), and the total diffuse light from AGC226067 is consistent with the luminosity function of the resolved ∼7-50 Myr stellar population. The main body of AGC226067 has a M V =−11.3±0.3, or M stars =5.4±1.3×104 M e given the stellar population. We searched 20 deg 2 of imaging data adjacent to AGC226067 in the Virgo Cluster, and found two similar stellar systems dominated by a blue stellar population, far from any massive galaxy counterpart-if this population has star-formation properties that are similar to those ofAGC226067, it implies ∼0.1 M e yr −1 in Virgo intracluster star formation. Given its unusual stellar population, AGC226067 is likely a stripped remnant and is plausibly the result of compressed gas from the ram pressure stripped M86 subgroup (∼350 kpc away in projection) as it falls into the Virgo Cluster.

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TWO LOCAL VOLUME DWARF GALAXIES DISCOVERED IN 21 cm EMISSION: PISCES A AND B

Cited by 40 publications

References 34 publications

Local ultra faint dwarves as a product of Galactic processing during a Magellanic group infall

Local ultra faint dwarves as a product of Galactic processing during a Magellanic group infall

What galaxy masses perturb the local cosmic expansion?

Hubble Space Telescope Imaging of the Ultra-compact High Velocity Cloud AGC 226067: A Stripped Remnant in the Virgo Cluster

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