The SAGA Survey. I. Satellite Galaxy Populations around Eight Milky Way Analogs

Geha, Marla; Wechsler, Risa H.; Mao, Yao-Yuan; Tollerud, Erik; Weiner, Benjamin J.; Bernstein, R. A.; Hoyle, B.; Marchi, S.; Marshall, Phil; Muñoz, Ricardo R.; Lu, Yu

doi:10.3847/1538-4357/aa8626

Cited by 260 publications

(339 citation statements)

References 92 publications

Supporting

Mentioning

320

Contrasting

Order By: Relevance

“…Objects that are undetected in HI but have optical distance measurements or lower limits that place them beyond M101 Figure 6. MV as a function of projected separation, Dproj, at the host distance for all known M101 satellites (maroon symbols; Tikhonov et al 2015;Danieli et al 2017;Bennet et al 2019) brighter than MV = −7.5, all known Milky Way/Local Group satellites down to that same limit (yellow symbols; 2015 update of McConnachie 2012), and satellites brighter than MV = −12.1 from the 8 spectroscopically complete hosts from the SAGA survey (horizontal dash-dotted line, Geha et al 2017). Stars denote satellites that are star forming or gas rich, and circles denote satellites that are quiescent or gas poor.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Neutral Hydrogen Observations of Low Surface Brightness Galaxies around M101 and NGC 5485

Karunakaran

Spekkens

Bennet

et al. 2020

View full text Add to dashboard Cite

We present atomic hydrogen (HI) observations using the Robert C. Byrd Green Bank Telescope along the lines-of-sight to 27 low surface brightness (LSB) dwarf galaxy candidates discovered in optical searches around M101. We detect HI reservoirs in 5 targets and place stringent upper limits on the remaining 22, implying that they are gas poor. The distances to our HI detections range from 7 Mpc -150 Mpc, demonstrating the utility of wide-bandpass HI observations as a follow-up tool. The systemic velocities of 3 detections are consistent with that of the NGC 5485 group behind M101, and we suggest that our 15 non-detections with lower distance limits from the optical are associated with and have been stripped by that group. We find that the gas richnesses of confirmed M101 satellites are broadly consistent with those of the Milky Way satellites, as well as with those of satellites around other hosts of comparable mass, when survey completeness is taken into account. This suggests that satellite quenching and gas stripping proceeds similarly around halos of similar mass, in line with theoretical expectations.

show abstract

Section: Discussionmentioning

confidence: 99%

“…M101 satellites with HI observations from this work are enclosed by black boxes, and the vertical dashed line indicates D proj = R vir . We adopt R vir = 260 kpc for M101 (Merritt et al 2014) and R vir = 300 kpc for the Milky Way and the SAGA hosts (see Geha et al 2017 for more detail). Fig.…”

Section: Satellite Gas Richnessmentioning

confidence: 99%

Neutral Hydrogen Observations of Low Surface Brightness Galaxies around M101 and NGC 5485

Karunakaran

Spekkens

Bennet

et al. 2020

View full text Add to dashboard Cite

show abstract

“…As shown in Figure 10, the majority of the contribution to this population is from galaxies with~-M 3 V , or M å ≈10 3 M e . With the continuing investment in observational efforts to compile a census of satellites around galaxies other than our own (see, e.g., the recent results from the SAGA survey; Geha et al 2017), the statistical significance of the features detected in the satellite luminosity function of the Milky Way and M31 may be confirmed. The prospect of also detecting satellites around less massive galaxies, such as the LMC, offers the possibility of a further test of current ideas about some of the most fundamental physical processes involved in galaxy formation.…”

Section: Discussionmentioning

confidence: 99%

The Imprint of Cosmic Reionization on the Luminosity Function of Galaxies

Bose

Deason

Frenk

2018

ApJ

View full text Add to dashboard Cite

The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractThe (re)ionization of hydrogen in the early universe has a profound effect on the formation of the first galaxies: by raising the gas temperature and pressure, it prevents gas from cooling into small halos, thus affecting the abundance of present-day small galaxies. Using the GALFORM semi-analytic model of galaxy formation, we show that two key aspects of the reionization process-when reionization takes place and the characteristic scale below which it suppresses galaxy formation-are imprinted in the luminosity function of dwarf galaxies. We focus on the luminosity function of satellites of galaxies like the Milky Way and the LMC, which is easier to measure than the luminosity function of the dwarf population as a whole. Our results show that the details of these two characteristic properties of reionization determine the shape of the luminosity distribution of satellites in a unique way, and are largely independent of the other details of the galaxy formation model. Our models generically predict a bimodality in the distribution of satellites as a function of luminosity: a population of faint satellites and population of bright satellites separated by a "valley" forged by reionization. We show that this bimodal distribution is present at high statistical significance in the combined satellite luminosity function of the Milky Way and M31. We make predictions for the expected number of satellites around LMC-mass dwarfs where the bimodality may also be measurable in future observational programs. Our preferred model predicts a total of 26±10 (68% confidence) satellites brighter than M V =0 in LMC-mass systems.

show abstract

“…Some studies include additional criteria, such as membership in a Local Group-like pair and isolation from Virgo-like galaxy clusters. As spectroscopic surveys, such as SAGA (Geha et al 2017) and DESI (DESI Collaboration et al 2016), begin to allow deep studies of galaxy-scale satellite systems outside the Local Volume, similar observational selections will need to be made for certain classes of science targets.…”

Section: The Prospects Of Selecting Milky Way-like Environmentsmentioning

confidence: 99%

The Sheet of Giants: Unusual properties of the Milky Way’s immediate neighbourhood

Neuzil

Mansfield

Kravtsov

2020

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We quantify the shape and overdensity of the galaxy distribution in the 'Local Sheet' within a sphere of R = 8 Mpc, and compare these properties with the expectations of the ΛCDM model. We measure ellipsoidal axis ratios of c/a ≈ 0.16 and b/a ≈ 0.79, indicating that the distribution of galaxies in the Local Volume can be approximated by a flattened oblate ellipsoid, consistent with the 'sheet'-like configuration noted in previous studies. In contrast with previous estimates that the Local Sheet has a density close to average, we find that the number density of faint and bright galaxies in the Local Volume is ≈ 1.7 and ≈ 5.2 times denser, respectively, than the mean number density of galaxies of the same luminosity. Comparison with simulations shows that the number density contrasts of bright and faint galaxies within 8 Mpc alone make the Local Volume a ≈ 2.5σ outlier in the ΛCDM cosmology. Our results indicate that the cosmic neighbourhood of the Milky Way may be unusual for galaxies of similar luminosity. The impact of the peculiar properties of our neighbourhood on the properties of the Milky Way and other nearby galaxies is not yet understood and warrants further study.

show abstract

The SAGA Survey. I. Satellite Galaxy Populations around Eight Milky Way Analogs

Cited by 260 publications

References 92 publications

Neutral Hydrogen Observations of Low Surface Brightness Galaxies around M101 and NGC 5485

Neutral Hydrogen Observations of Low Surface Brightness Galaxies around M101 and NGC 5485

The Imprint of Cosmic Reionization on the Luminosity Function of Galaxies

The Sheet of Giants: Unusual properties of the Milky Way’s immediate neighbourhood

Contact Info

Product

Resources

About