r-process Enrichment of the Ultra-faint Dwarf Galaxies by Fast-merging Double-neutron Stars

Safarzadeh, Mohammadtaher; Ramírez-Ruiz, E.; Andrews, Jeff J.; Macias, Phillip; Fragos, Tassos; Scannapieco, Evan

doi:10.3847/1538-4357/aafe0e

Cited by 56 publications

(53 citation statements)

References 78 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The existence of such a fast-merging channel would have profound implications on the presence of r-process elements in the Universe. Recent studies have shown that, if r-process enrichment seen in the ultra-faint dwarf galaxies Reticulum II and Tucana III is formed from the merger of DNSs, then a fast-merging channel is required (Beniamini & Piran 2016;Safarzadeh et al 2019a). Similar arguments are required to explain the existence of r-process enrichment in globular clusters (Zevin et al 2019).…”

Section: A Fast-merging Channel?mentioning

confidence: 97%

LISA and the Existence of a Fast-merging Double Neutron Star Formation Channel

Andrews

Breivik

Pankow

et al. 2020

ApJL

Self Cite

View full text Add to dashboard Cite

Using a Milky Way double neutron star (DNS) merger rate of 210 Myr −1 , as derived by the Laser Interferometer Gravitational-Wave Observatory (LIGO), we demonstrate that the Laser Interferometer Space Antenna (LISA) will detect on average 240 (330) DNSs within the Milky Way for a 4-year (8year) mission with a signal-to-noise ratio greater than 7. Even adopting a more pessimistic rate of 42 Myr −1 , as derived by the population of Galactic DNSs, we find a significant detection of 46 (65) Milky Way DNSs. These DNSs can be leveraged to constrain formation scenarios. In particular, traditional NS-discovery methods using radio telescopes are unable to detect DNSs with P orb 1 hour (merger times 10 Myr). If a fast-merging channel exists that forms DNSs at these short orbital periods, LISA affords, perhaps, the only opportunity to observationally characterize these systems; we show that toy models for possible formation scenarios leave unique imprints on DNS orbital eccentricities, which may be measured by LISA for values as small as ∼10 −2 .

show abstract

Section: A Fast-merging Channel?mentioning

confidence: 97%

LISA and the Existence of a Fast-merging Double Neutron Star Formation Channel

Andrews

Breivik

Pankow

et al. 2020

ApJL

Self Cite

View full text Add to dashboard Cite

show abstract

“…Indeed, Rodney et al (2014) found that observations suggest a prompt fraction of up to 50% (defined as events with delay times of <500 Myr), with the results fully consistent with a power-law DTD with η=1. For BNS mergers, most recent simulations require a prompt channel to explain r-process enrichment in Milky Way stars and ultrafaint dwarf galaxies (Matteucci et al 2014;Beniamini et al 2016a;Safarzadeh et al 2019c;Simonetti et al 2019). A reliable estimate of the prompt SGRB fraction would require a careful assessment of observational biases, the true SGRB redshift distribution, and stellar population ages as a proxy for the progenitor age distribution.…”

Section: Sgrb Redshift Distribution and Implications For Delay Timesmentioning

confidence: 99%

Discovery of the Optical Afterglow and Host Galaxy of Short GRB 181123B at z = 1.754: Implications for Delay Time Distributions

Paterson

Fong

Nugent

et al. 2020

ApJL

View full text Add to dashboard Cite

We present the discovery of the optical afterglow and host galaxy of the Swift short-duration gamma-ray burst (SGRB) GRB 181123B. Observations with Gemini-North starting ≈9.1 hr after the burst reveal a faint optical afterglow with i≈25.1 mag at an angular offset of 0 59±0 16 from its host galaxy. Using grizYJHK observations, we measure a photometric redshift of the host galaxy of =-+ z 1.77 0.17 0.30. From a combination of Gemini and Keck spectroscopy of the host galaxy spanning 4500-18000 Å, we detect a single emission line at 13390 Å, inferred as Hβ at z=1.754±0.001 and corroborating the photometric redshift. The host galaxy properties of GRB 181123B are typical of those of other SGRB hosts, with an inferred stellar mass of ≈9.1×10 9 M e , a mass-weighted age of ≈0.9 Gyr, and an optical luminosity of ≈0.9L *. At z=1.754, GRB 181123B is the most distant secure SGRB with an optical afterglow detection and one of only three at z>1.5. Motivated by a growing number of high-z SGRBs, we explore the effects of a missing z>1.5 SGRB population among the current Swift sample on delay time distribution (DTD) models. We find that lognormal models with mean delay times of ≈4-6 Gyr are consistent with the observed distribution but can be ruled out to 95% confidence, with an additional ≈one to five Swift SGRBs recovered at z>1.5. In contrast, power-law models with ∝t −1 are consistent with the redshift distribution and can accommodate up to ≈30 SGRBs at these redshifts. Under this model, we predict that ≈1/3 of the current Swift population of SGRBs is at z>1. The future discovery or recovery of existing high-z SGRBs will provide significant discriminating power on their DTDs and thus their formation channels.

show abstract

“…These authors concluded that this transient (kilonova) was powered by the radioactive decay of large amounts of r-process elements, in agreement with early theoretical predictions (Lattimer & Schramm 1974). It has been suggested that neutron star mergers are the primary (perhaps the only) source of r-process enrichment in the Galaxy (e.g., Côté et al 2018;Safarzadeh et al 2019a;Banerjee et al 2020;Dvorkin et al 2020), but other studies (Belczynski et al 2018;Ji & Frebel 2018;Ji et al 2019;Côté et al 2019;Safarzadeh et al 2019b;Haynes & Kobayashi 2019;Kobayashi et al 2020) have provided evidence that additional sources may be involved.…”

mentioning

confidence: 99%

GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral

Abbott¹,

Abbott²,

Abbott³

et al. 2017

View full text Add to dashboard Cite

Gravitationswellen -ein leichtes Zittern der raumzeitVor 1,3 Milliarden Jahren: Seit langer Zeit schon haben sich in einer fernen Galaxie zwei schwarze Löcher umkreist, Gebilde von so ungeheurer Dichte, das selbst Licht ihrer Schwerkraft nicht mehr entweichen kann und von ihnen eingefangen wird. Seit Jahrmillionen haben sie bei ihrem Tanz umeinander mit ihrer masse die Raumzeit verformt und dabei Gravitationswellen abgestrahlt. ihr Abstand wurde dabei immer kleiner, ihre Geschwindigkeit immer höher, bis sie schließlich unter einem gewaltigen Ausbruch von Gravitationswellen zu einem einzelnen schwarzen Loch verschmelzen. Später werden wir diese Wellen GW150914 nennen. Für einen kurzen Augenblick wird durch sie mehr Leistung abgestrahlt als von allen Sternen im gesamten sichtbaren Universum in Form von elektromagnetischer Strahlung zusammen. Diese Gravitationswellen rasen mit Lichtgeschwindigkeit durch das Weltall und lassen auf ihrem Weg die Raumzeit erzittern.25. November 1915: GW150914 ist schon längst in unserer milchstra-

show abstract

r-process Enrichment of the Ultra-faint Dwarf Galaxies by Fast-merging Double-neutron Stars

Cited by 56 publications

References 78 publications

LISA and the Existence of a Fast-merging Double Neutron Star Formation Channel

LISA and the Existence of a Fast-merging Double Neutron Star Formation Channel

Discovery of the Optical Afterglow and Host Galaxy of Short GRB 181123B at z = 1.754: Implications for Delay Time Distributions

GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral

Contact Info

Product

Resources

About