Tidal Stream Morphology as an Indicator of Dark Matter Halo Geometry: The Case of Palomar 5

Pearson, Sarah; Küpper, Andreas H. W.; Johnston, Kathryn V.; Price-Whelan, Adrian M.

doi:10.1088/0004-637x/799/1/28

Cited by 82 publications

(136 citation statements)

References 58 publications

Supporting

Mentioning

129

Contrasting

Order By: Relevance

“…The second is the shape of the gravitational potential. For instance, triaxial potentials tend to increase the fanning of stream stars significantly (Pearson et al 2015;PriceWhelan et al 2016). However, there is evidence that the inner halo of the Galaxy is relatively spherical out to ∼20 kpc, thus allowing us to assume the stream width maps only to the progenitor size and velocity dispersion.…”

Section: Possible Progenitorsmentioning

confidence: 99%

The Phoenix Stream: A Cold Stream in the Southern Hemisphere

Balbinot¹,

Yanny²,

Li³

et al. 2016

ApJ

View full text Add to dashboard Cite

We report the discovery of a stellar stream in the Dark Energy Survey Year 1 (Y1A1) data. The discovery was made through simple color-magnitude filters and visual inspection of the Y1A1 data. We refer to this new object as the Phoenix stream, after its resident constellation. After subtraction of the background stellar population we detect a clear signal of a simple stellar population. By fitting the ridge line of the stream in color-magnitude space, we find that a stellar population with age τ=11.5±0.5 Gyr and [Fe/H]<−1.6, located 17.5±0.9 kpc from the Sun, gives an adequate description of the stream stellar population. The stream is detected over an extension of 8°.1 (2.5 kpc) and has a width of ∼54 pc assuming a Gaussian profile, indicating that a globular cluster (GC) is a probable progenitor. There is no known GC within 5 kpc that is compatible with being the progenitor of the stream, assuming that the stream traces its orbit. We examined overdensities (ODs) along the stream, however, no obvious counterpart-bound stellar system is visible in the coadded images. We also find ODs along the stream that appear to be symmetrically distributed-consistent with the epicyclic OD scenario for the formation of cold streams-as well as a misalignment between the northern and southern part of stream. Despite the close proximity we find no evidence that this stream and the halo cluster NGC 1261 have a common accretion origin linked to the recently found EriPhe OD.

show abstract

Section: Possible Progenitorsmentioning

confidence: 99%

The Phoenix Stream: A Cold Stream in the Southern Hemisphere

Balbinot¹,

Yanny²,

Li³

et al. 2016

ApJ

View full text Add to dashboard Cite

show abstract

“…As discussed above, this can be attributed to the wider variety of orbits that the VL-2 halo permits due to its lack of dynamical symmetry. In particular, extremely "fluffy" streams can be found in Figure 5 and have been investigated in more detail by Ngan et al (2015), Pearson et al (2015), Price-Whelan et al (2016).…”

Section: Dispersal Of Tidal Debrismentioning

confidence: 99%

Dispersal of Tidal Debris in a Milky-Way-Sized Dark Matter Halo

Ngan

Carlberg

Bozek

et al. 2016

ApJ

View full text Add to dashboard Cite

We simulate the tidal disruption of a collisionless N-body globular star cluster in a total of 300 different orbits selected to have galactocentric radii between 10 and 30 kpc in four dark matter halos: (a) a spherical halo with no subhalos, (b) a spherical halo with subhalos, (c) a realistic halo with no subhalos, and (d) a realistic halo with subhalos. This allows us to isolate and study how the halo's (lack of) dynamical symmetry and substructures affect the dispersal of tidal debris. The realistic halos are constructed from the snapshot of the Via Lactea II simulation at redshift zero. We find that the overall halo's symmetry disperses tidal debris to make the streams fluffier, consistent with previous studies of tidal debris of dwarf galaxies in larger orbits than ours in this study. On the other hand, subhalos in realistic potentials can locally enhance the densities along streams, making streams denser than their counterparts in smooth potentials. We show that many long and thin streams can survive in a realistic and lumpy halo for a Hubble time. This suggests that upcoming stellar surveys will likely uncover more thin streams which may contain density gaps that have been shown to be promising probes for dark matter substructures.

show abstract

“…Recent theoretical work on streams (Pearson et al 2015) found that cold N-body streams simulated in a triaxial potential can exhibit a rather abrupt spreading in position and velocity space at the seeming ends of the cold stream, which they named stream-fanning (see their Figure 4). This fanning may arise if the progenitor is on a chaotic orbit, common in triaxial or otherwise complex gravitational potentials (bottom panels of Figure 11 of Fardal et al 2015; Figure 7 of Price-Whelan et al 2015); or it may arise through interactions with dark matter subhalos (bottom left panel of Figure 3 of Bonaca et al 2014).…”

Section: Introductionmentioning

confidence: 99%

“…This fanning may arise if the progenitor is on a chaotic orbit, common in triaxial or otherwise complex gravitational potentials (bottom panels of Figure 11 of Fardal et al 2015; Figure 7 of Price-Whelan et al 2015); or it may arise through interactions with dark matter subhalos (bottom left panel of Figure 3 of Bonaca et al 2014). Hence, stream-fanning-if observable-could become a new tool for studying these dynamical phenomena.…”

Section: Introductionmentioning

confidence: 99%

“…Hence, stream-fanning-if observable-could become a new tool for studying these dynamical phenomena. In a first application, Pearson et al (2015) used the absence of fanning in the known long and cold stream of the globular cluster Palomar 5 (Pal 5) (Odenkirchen et al 2001) to rule out the Law & Majewski (2010) (triaxial) dark matter halo potential within r 25 kpc  . Stream-fanning may turn out to be the most plausible explanation for the stellar population versus age tension in the Ophiuchus stream.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Evidence of Fanning in the Ophiuchus Stream

Sesar

Price-Whelan

Cohen

et al. 2015

ApJL

Self Cite

View full text Add to dashboard Cite

The Ophiuchus stellar stream presents a dynamical puzzle: its old stellar populations (∼12 Gyr) cannot be reconciled with (1) its orbit in a simple model for the Milky Way potential and (2) its short angular extent, both of which imply that the observed stream formed within the last 1 Gyr < . Recent theoretical work has shown that streams on chaotic orbits may abruptly fan out near their apparent ends; stars in these fans are dispersed in both position and velocity and may be difficult to associate with the stream. Here we present the first evidence of such stream-fanning in the Ophiuchus stream, traced by four blue horizontal branch stars beyond the apparent end of the stream. These stars stand out from the background by their high velocities (v 230 los > km s −1 ) against ∼40 other stars: their velocities are comparable to those of the stream, but would be exceptional if they were unrelated halo stars. Their positions and velocities are, however, inconsistent with simple extrapolation of the observed cold, high-density portion of the stream. These observations suggest that stream-fanning may be a real, observable effect and, therefore, that Ophiuchus may be on a chaotic orbit. They also show that the Ophiuchus stream is more extended and hence dynamically older than previously thought, easing the stellar population versus dynamical age tension.

show abstract

Tidal Stream Morphology as an Indicator of Dark Matter Halo Geometry: The Case of Palomar 5

Cited by 82 publications

References 58 publications

The Phoenix Stream: A Cold Stream in the Southern Hemisphere

The Phoenix Stream: A Cold Stream in the Southern Hemisphere

Dispersal of Tidal Debris in a Milky-Way-Sized Dark Matter Halo

Evidence of Fanning in the Ophiuchus Stream

Contact Info

Product

Resources

About