Discovery of New Dwarf Galaxies in the M81 Group

Chiboucas, Kristin; Караченцев, И. Д.; Tully, R. Brent

doi:10.1088/0004-6256/137/2/3009

Cited by 134 publications

(200 citation statements)

References 93 publications

Supporting

Mentioning

190

Contrasting

Order By: Relevance

“…They are easily exposed to the sweep-out of gas from their shallow potential wells. A special search for such ultra-dwarfs in the vicinity of M 81 (Chiboucas et al 2009(Chiboucas et al , 2013 confirms that they are dominated by quenching objects with no signs of star formation (Kaisin & Karachentsev 2013). …”

Section: Segregation Of Companions By Morphological Typesmentioning

confidence: 87%

Companions around the nearest luminous galaxies: Segregation and selection effects

Караченцев

Kudrya

2015

Astron Nachr

View full text Add to dashboard Cite

Using the "Updated Nearby Galaxy Catalog", we consider different properties of companion galaxies around luminous hosts in the Local Volume. The data on stellar masses, linear diameters, surface brightnesses, HI-richness, specific star formation rate (sSF R), and morphological types are discussed for members of the nearest groups, including the Milky Way and M 31 groups, as a function of their separation from the hosts. Companion galaxies in groups tend to have lower stellar masses, smaller linear diameters and fainter mean surface brightnesses as the distance to their host decreases. The hydrogen-to-stellar mass ratio of the companions increases with their linear projected separation from the dominant luminous galaxy. This tendency is more expressed around the bulge-dominated hosts. While linear separation of the companions decreases, their mean sSF R becomes lower, accompanied with the increasing sSF R scatter. Typical linear projected separation of dSphs around the bulge-dominated hosts, 350 kpc, is substantially larger than that around the disk-dominated ones, 130 kpc. This difference probably indicates the presence of larger hot/warm gas haloes around the early-type host galaxies. The mean fraction of dSph (quenched) companions in 11 the nearest groups as a function of their projected separation Rp can be expressed as f (E) = 0.55 − 0.69 × Rp. The fraction of dSphs around the Milky Way and M 31 looks much higher than in other nearby groups because the quenching efficiency dramatically increases towards the ultra-low mass companions. We emphasize that the observed properties of the Local Group are not typical for other groups in the Local Volume due to the role of selection effects caused by our location inside the Local Group.

show abstract

Section: Segregation Of Companions By Morphological Typesmentioning

confidence: 87%

Companions around the nearest luminous galaxies: Segregation and selection effects

Караченцев

Kudrya

2015

Astron Nachr

View full text Add to dashboard Cite

show abstract

“…This faint object of very low surface brightness was discovered by Chiboucas et al (2009) as a probable background galaxy behind the M 81 group. There is a strong disagreement between its low luminosity and the broad HI line width, leading to M T /L B ∼ 184 2 and M HI /L B = 30 in solar units.…”

Section: D0946+6842mentioning

confidence: 87%

HI-observations of dwarf galaxies in the Local Supercluster

Huchtmeier

Караченцев

Караченцева³

2009

A&A

View full text Add to dashboard Cite

We have observed 71 dwarf galaxies of low surface brightness using the 100-m radio telescope at Effelsberg in a search for new members of 27 northern galaxy groups with characteristic distances of 8 to 15 Mpc. We present radial velocities, HI-fluxes, and HI line widths for 17 detected galaxies as well as upper limits for the remaining undetected objects. Almost all detected dwarf galaxies are physical members of the corresponding group with a mean radial velocity difference of −9 ± 45 km s −1 with respect to the principal galaxy in each group. Our sample of new dwarf members of nearby groups has a median radial velocity of 700 km s −1 , a mean blue absolute magnitude of -12.7 mag, a mean linear diameter of 2.5 kpc, and a mean M HI /L B ratio of 1.1 M /L . The Ir galaxy d1217+4703 in the Canes Venatici I cloud turns out to be a very gas-rich galaxy with M HI /L B = 6.5 in solar units.

show abstract

“…We will apply this same technique to the newly discovered dwarf satellites of M81 located at ∼3.8 Mpc (Chiboucas et al 2009(Chiboucas et al , 2013 and to the dwarf galaxies and streams that Figure 8. Metallicity-luminosity relation for dwarf galaxies.…”

Section: Discussionmentioning

confidence: 99%

“…Thus, it is important to make a systematic study of these faint structures beyond the Local Group and understand whether these inconsistencies between ΛCDM and observations are a consequence of the Local Group being an outlier or whether some of the physics considered in these simulations needs to be adjusted. Some efforts have begun in this direction (Chiboucas et al 2009(Chiboucas et al , 2013Crnojević et al 2014;Sand et al 2014;Toloba et al 2016), but they are generally limited to photometric information. Spectroscopy of these faint structures and satellites provides dynamical information to model the disruptive events and predict their timescales as well as information on stellar metallicity to learn about their star formation histories.…”

Section: Introductionmentioning

confidence: 99%

New Spectroscopic Technique Based on Coaddition of Surface Brightness Fluctuations: NGC 4449 and Its Stellar Tidal Stream

Toloba

Guhathakurta

Romanowsky

et al. 2016

ApJ

View full text Add to dashboard Cite

We present a new spectroscopic technique based in part on targeting the upward fluctuations of the surface brightness for studying the internal stellar kinematics and metallicities of galaxies of low surface brightness effects both to galaxies and streams beyond the Local Group. The distance to these systems makes them unsuitable for targeting individual red giant branch (RGB) stars (tip of RGB at  I 24 mag) and their surface brightness is too low (  m 25 r mag arcsec −2 ) for integrated light spectroscopic measurements. This technique overcomes these two problems by targeting individual objects that are brighter than the tip of the RGB. We apply this technique to the star-forming dwarf galaxy NGC 4449 and its stellar stream. We use Keck/DEIMOS data to measure the line-ofsight radial velocity out to ∼7 kpc in the east side of the galaxy and ∼8 kpc along the stream. We find that the two systems are likely gravitationally bound to each other and have heliocentric radial velocities of 227.3 ± 10.7 km s −1 and 225.8 ± 16.0 km s −1 , respectively. Neither the stream nor the near half of the galaxy shows a significant velocity gradient. We estimate the stellar metallicity of the stream based on the equivalent width of its calcium triplet lines and find [Fe/H] = - 1.37 0.41, which is consistent with the metallicity-luminosity relation for dwarf galaxies in the Local Group. Whether the streamʼs progenitor was moderately or severely stripped cannot be constrained with this uncertainty in metallicity. We demonstrate that this new technique can be used to measure the kinematics and (possibly) the metallicity of the numerous faint satellites and stellar streams in the halos of nearby (∼4 Mpc) galaxies.

show abstract

Discovery of New Dwarf Galaxies in the M81 Group

Cited by 134 publications

References 93 publications

Companions around the nearest luminous galaxies: Segregation and selection effects

Companions around the nearest luminous galaxies: Segregation and selection effects

HI-observations of dwarf galaxies in the Local Supercluster

New Spectroscopic Technique Based on Coaddition of Surface Brightness Fluctuations: NGC 4449 and Its Stellar Tidal Stream

Contact Info

Product

Resources

About