A sharper view of Pal 5's tails: discovery of stream perturbations with a novel non-parametric technique

Erkal, Denis; Koposov, S. E.; Belokurov, V.

doi:10.1093/mnras/stx1208

Cited by 128 publications

(171 citation statements)

References 87 publications

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“…smoothing.html footprint (e.g., close to the Galactic disk, LMC, or Sagittarius stream). For these reasons, we perform an unweighted matched-filter search, where stars are simply accepted or rejected based on their location in color-magnitude space (e.g., Erkal et al 2017). As a validation, we repeated our search following the procedure of Rockosi et al (2002) to build a matched-filter isochrone from the CMDs of the globular cluster NGC 7089 and the average Milky Way foreground population.…”

Section: Matched-filter Selectionmentioning

confidence: 99%

“…Observations of stellar streams can provide important constraints on the formation of the Milky Way stellar halo (e.g., Johnston 1998; Bullock & Johnston 2005;Bell et al 2008), the shape of the Galactic gravitational field (e.g., Johnston et al 2005;Koposov et al 2010;Law & Majewski 2010;Bonaca et al 2014;Bovy 2014;Gibbons et al 2014;PriceWhelan et al 2014;Sanders 2014;Bowden et al 2015;Küpper et al 2015;Erkal et al 2016b;Bovy et al 2016), and the abundance of low-mass dark matter substructure (e.g., Ibata et al 2002;Johnston et al 2002;Carlberg 2009;Yoon et al 2011;Carlberg 2012;Ngan & Carlberg 2014;Erkal & Belokurov 2015a;Carlberg 2016;Sanderson et al 2016;Sanders et al 2016;Bovy et al 2017;Erkal et al 2017;Sandford et al 2017). In addition, stellar streams are a direct snapshot of hierarchical structure formation (Peebles 1965;Press & Schechter 1974;Blumenthal et al 1984) and support the standard ΛCDM cosmological model (Diemand et al 2008;Springel et al 2008).…”

Section: Introductionmentioning

confidence: 99%

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Stellar Streams Discovered in the Dark Energy Survey

Shipp

Drlica-Wagner

Balbinot

et al. 2018

ApJ

255

254

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We perform a search for stellar streams around the Milky Way using the first 3 yr of multiband optical imaging data from the Dark Energy Survey (DES). We use DES data covering ∼5000 deg 2 to a depth of g>23.5 with a relative photometric calibration uncertainty of <1%. This data set yields unprecedented sensitivity to the stellar density field in the southern celestial hemisphere, enabling the detection of faint stellar streams to a heliocentric distance of ∼50 kpc. We search for stellar streams using a matched filter in color-magnitude space derived from a synthetic isochrone of an old, metal-poor stellar population. Our detection technique recovers four previously known thin stellar streams: Phoenix, ATLAS, Tucana III, and a possible extension of Molonglo. In addition, we report the discovery of 11 new stellar streams. In general, the new streams detected by DES are fainter, more distant, and lower surface brightness than streams detected by similar techniques in previous photometric surveys. As a by-product of our stellar stream search, we find evidence for extratidal stellar structure associated with four globular clusters: NGC 288, NGC 1261, NGC 1851, and NGC 1904. The ever-growing sample of stellar streams will provide insight into the formation of the Galactic stellar halo, the Milky Way gravitational potential, and the large-and small-scale distribution of dark matter around the Milky Way.

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Section: Matched-filter Selectionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Stellar Streams Discovered in the Dark Energy Survey

Shipp

Drlica-Wagner

Balbinot

et al. 2018

ApJ

255

254

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“…For simplicity, we assume a circular orbit with a distance from the center of the Galaxy of R GC = 15 kpc, which is similar to the average of Pal 5's apocentric and pericentric distance for its rather elliptical orbit (see e.g. Erkal et al 2017).…”

Section: Length and Width Of Streamsmentioning

confidence: 99%

Detecting Thin Stellar Streams in External Galaxies: Resolved Stars and Integrated Light

Pearson

Starkenburg

Johnston

et al. 2019

ApJ

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The morphology of thin stellar streams can be used to test the nature of dark matter. It is therefore crucial to extend searches for globular cluster streams to other galaxies than the Milky Way. In this paper, we investigate the current and future prospects of detecting globular cluster streams in external galaxies in resolved stars (e.g. with WFIRST) and using integrated light (e.g. with HSC, LSST and Euclid). In particular, we inject mock-streams to data from the PAndAS M31 survey, and produce simulated M31 backgrounds mimicking what WFIRST will observe in M31. Additionally, we estimate the distance limit to which globular cluster streams will be observable. Our results demonstrate that for a 1 hour (1000 sec.) exposure, using conservative estimates, WFIRST should detect globular cluster streams in resolved stars in galaxies out to distances of ∼3.5 Mpc (∼2 Mpc). This volume contains 199 (122) galaxies of which >90% are dwarfs. With integrated light, thin streams can be resolved out to ∼100 Mpc with HSC and LSST and to ∼600 Mpc with WFIRST and Euclid. The low surface brightness of the streams (typically >30 mag/arcsec 2 ), however, will make them difficult to detect, unless the streams originate from very young clusters. We emphasize that if the external galaxies do not host spiral arms or galactic bars, gaps in their stellar streams provide an ideal test case for evidence of interactions with dark matter subhalos. Furthermore, obtaining a large samples of thin stellar streams can help constrain the orbital structure and hence the potentials of external halos.

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“…Carlberg 2009;Yoon, Johnston & Hogg 2011;Carlberg 2012;Erkal & Belokurov 2015a), which are not observable by conventional methods (Ikeuchi 1986;Rees 1986). Indeed, tentative evidence for a disturbance by low mass subhaloes has been found in the Pal 5 stream (Bovy, Erkal & Sanders 2017;Erkal, Koposov & Belokurov 2017). One of the difficulties in uncovering the origin of details in the stream morphology is related to the uniqueness of the signature left by an encounter with a dark subhalo (Yoon, Johnston & Hogg 2011;Carlberg 2012;Erkal & Belokurov 2015a;.…”

Section: Introductionmentioning

confidence: 99%

A closer look at the spur, blob, wiggle, and gaps in GD-1

Boer

Erkal

Gieles

2020

Monthly Notices of the Royal Astronomical Society

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The GD-1 stream is one of the longest and coldest stellar streams discovered to date, and one of the best objects for constraining the dark matter properties of the Milky Way. Using data from Gaia DR2 we study the proper motions, distance, morphology and density of the stream to uncover small scale perturbations. The proper motion cleaned data shows a clear distance gradient across the stream, ranging from 7 to 12 kpc. However, unlike earlier studies that found a continuous gradient, we uncover a distance minimum at ϕ 1 ≈-50 deg, after which the distance increases again. We can reliably trace the stream between -85< ϕ 1 <15 deg, showing an even further extent to GD-1 beyond the earlier extension of Price-Whelan & Bonaca (2018). We constrain the stream track and density using a Boolean matched filter approach and find three large under densities and find significant residuals in the stream track lining up with these gaps. In particular, a gap is visible at ϕ 1 =-3 deg, surrounded by a clear sinusoidal wiggle. We argue that this wiggle is due to a perturbation since it has the wrong orientation to come from a progenitor. We compute a total initial stellar mass of the stream segment of 1.58±0.07×10 4 M . With the extended view of the spur in this work, we argue that the spur may be unrelated to the adjacent gap in the stream. Finally, we show that an interaction with the Sagittarius dwarf can create features similar to the spur.

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A sharper view of Pal 5's tails: discovery of stream perturbations with a novel non-parametric technique

Cited by 128 publications

References 87 publications

Stellar Streams Discovered in the Dark Energy Survey

Stellar Streams Discovered in the Dark Energy Survey

Detecting Thin Stellar Streams in External Galaxies: Resolved Stars and Integrated Light

A closer look at the spur, blob, wiggle, and gaps in GD-1

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