adsabs/FOCAL huggingface dataset:
Also addressing the evolution of a stellar cluster is work by Parker & Goodwin (2009) and Parker et al. (2009) in which N-body simulations are used to analyse the prevalence of planets susceptible to the Kozai effect from a binary companion, and the stability of binaries in a dense cluster environment respectively. Parker & Goodwin (2009) found that around $20{{\ \rm per\ cent}}$ of all exoplanets should at one point in their lives be in the presence of a binary companion that has been sufficiently inclined by its cluster environment such that Kozai cycles can occur. This is an intriguing finding that bolsters the idea that a binary companion perturbed by the cluster can have an appreciable effect on the planets, with the caveat that the authors only examined the evolution of binary orbits, as their simulations lacked planetary bodies. Additionally, they particularly focused on very dense clusters similar to Orion, with a half-mass radius of only 0.1 pc. This is not typical for embedded clusters, which have typical half mass radii of ∼0.8 pc (Lada & Lada 2003), and therefore would have less frequent interactions between cluster stars and a particular binary. Nevertheless, they showed that a dense cluster environment can significantly alter the architecture of a stellar binary which in turn can affect a protoplanetary disc or mature planet system. Parker et al. (2009) focused on similarly dense cluster environments, but instead explored the longevity of moderately wide (${\sim }10^3 \, \text{au}$) to ultrawide (${\gt}10^4 \, \text{au}$) binaries. They found that cluster environments strip away all ultra-wide binary companions, and that the denser clusters, with half mass radii of 0.1–0.2 pc do not retain any binaries with separations ${\gt}10^3 \, \text{au}$. The less dense clusters, with half mass radii 0.4–0.8 pc, do retain some of these moderately wide binaries. The authors noted that as ultrawide binaries are often stripped in only a few cluster crossing times, these very separated binaries may form in isolation An alternate channel is that ultrawide binaries are formed during cluster dissolution (Kouwenhoven et al. 2010).
Citation: Lada & Lada 2003
Citation function: Differences; Differences
A variety of formation channels have been proposed for binary black holes (BBHs; see e.g. Mapelli 2021 for a recent review): BBH mergers can be the outcome of isolated binary evolution via common envelope (Tutukov & Yungelson 1973; Bethe & Brown 1998; Portegies Zwart & Yungelson 1998; Belczynski, Kalogera & Bulik 2002; Belczynski et al. 2008, 2016a; Dvorkin et al. 2016, 2018; Eldridge & Stanway 2016; Mapelli et al. 2017, 2019; Stevenson, Berry & Mandel 2017; Kruckow et al. 2018; Spera et al. 2019; Belczynski et al. 2020; Klencki et al. 2021; Olejak, Belczynski & Ivanova 2021; Tanikawa et al. 2021a), stable mass transfer (Giacobbo, Mapelli & Spera 2018; Neijssel et al. 2019; Bavera et al. 2021; Gallegos-Garcia et al. 2021; Shao & Li 2021), or chemically homogeneous evolution (de Mink & Mandel 2016; Mandel & de Mink 2016; Marchant et al. 2016; du Buisson et al. 2020; Riley et al. 2021). Alternatively, BBHs can form dynamically in triples (e.g. Antonini, Toonen & Hamers 2017; Silsbee & Tremaine 2017; Fragione & Silk 2020; Arca Sedda, Li & Kocsis 2021a; Vigna-Gómez et al. 2021), multiples (e.g. Fragione & Kocsis 2019; Liu & Lai 2019, 2021; Hamers & Safarzadeh 2020), young star clusters (YSCs; Banerjee, Baumgardt & Kroupa 2010; Mapelli 2016; Banerjee 2017, 2021; Di Carlo et al. 2019, 2020a; Kumamoto, Fujii & Tanikawa 2019, 2020), globular clusters (GCs; Portegies Zwart & McMillan 2000; Tanikawa 2013; Samsing, MacLeod & Ramirez-Ruiz 2014; Rodriguez, Chatterjee & Rasio 2016; Askar et al. 2017; Fragione & Kocsis 2018; Hong et al. 2018; Choksi et al. 2019; Kamlah et al. 2022), and nuclear star clusters (NSCs; Antonini & Rasio 2016; Petrovich & Antonini 2017; Antonini, Gieles & Gualandris 2019; Arca Sedda 2020; Arca Sedda et al. 2020; Fragione, Loeb & Rasio 2020). Furthermore, gas torques in active galactic nucleus (AGN) discs trigger the formation of BBHs and speed up their mergers (e.g. Bartos et al. 2017; Stone, Metzger & Haiman 2017; McKernan et al. 2018; Yang et al. 2019; Ishibashi & Gröbner 2020; Tagawa, Haiman & Kocsis 2020). Finally, primordial black holes (BHs), born from gravitational collapses in the early Universe, might also pair up and merge via gravitational wave (GW) emission (e.g. Carr & Hawking 1974; Carr, Kühnel & Sandstad 2016; Sasaki et al. 2016; Ali-Haïmoud, Kovetz & Kamionkowski 2017; Clesse & García-Bellido 2017; De Luca et al. 2021).
Citation: Liu & Lai 2019
Citation function: Background; Background
While most systems with exo-Kuiper belts do not have known planetary mass companions, in a few of these it has been possible to directly image one, thus enabling the study of planet–disc interactions in more detail. There are well-known examples such as β Pic with a massive planet possibly warping the disc (Mouillet et al. 1997; Lagrange et al. 2012, 2019; Matrà et al. 2019); HR 8799 with four giant planets creating a scattered disc and possibly replenishing its warm dust closer in (e.g. Marois et al. 2010; Booth et al. 2016; Zurlo et al. 2016; Read et al. 2018; Wilner et al. 2018; Geiler et al. 2019; Faramaz et al., in preparation); HD 95086’s axisymmetric disc implying a low eccentricity of its 4MJup planet (Rameau et al. 2016; Su et al. 2017); and Fomalhaut having a narrow and eccentric planetesimal belt (Kalas, Graham & Clampin 2005; Acke et al. 2012; Boley et al. 2012; MacGregor et al. 2017), implying that its candidate companion on an eccentric orbit has a low mass (∼Earth or super-Earth) and is not sculpting the belt (Quillen 2006; Kalas et al. 2008; Chiang et al. 2009; Beust et al. 2014; Faramaz et al. 2015), or is not a compact object but rather the dusty aftermath of a recent planetesimal collision (Gaspar & Rieke 2020). Some exo-Kuiper belt host systems even have companions in the brown dwarf (BD) or low stellar mass regime, suggesting that their likely formation through gravitational instability (Boss 1997, 2003, 2011; Vorobyov 2013) is compatible with the formation of massive Kuiper belt analogues, e.g. HR 2562 (Konopacky et al. 2016), HD 193571 (Musso Barcucci et al. 2019), HD 92536 (Launhardt et al. 2020), and HD 206893 (Milli et al. 2017). The last one is the subject of this paper. For even more massive companions, Yelverton et al. (2019) found a significant lower detection rate of debris discs around binaries, with no discs detected in binaries with separations between 25 and 135 au (comparable to typical debris disc radii; Matrà et al. 2018b). This is likely due to dynamical perturbation inhibiting planetesimal formation or clearing any debris disc formed near those separations.
Citation: MacGregor et al. 2017
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In this paper, we focus on the bright elliptical galaxy NGC 5813. This is the central dominant member of a subgroup, hereafter referred to as the NGC 5813 group with an extensive diffuse X-ray emission. While part of the well-isolated NGC 5846 group ($z$ = 0.006578; e.g. Mahdavi, Trentham & Tully 2005a; Machacek et al. 2011) with a projected separation of ∼740 kpc, the two show no signs of an interaction between them. NGC 5813 itself has been assumed to be dynamically old (Emsellem et al. 2007) with no evidence of a recent major merger in its history, as indicated by the lack of any significant disturbances to its dusty circumnuclear disc (Tran et al. 2001). Regarding its atmosphere, the NGC 5813 group has a rather well defined regular morphology, consisting of three collinear pairs of cavities and associated shock fronts that are products of three distinct outburst events in the central AGN’s history (Randall et al. 2011). Such cavities often appear as a result of AGN-ICM or IGrM interaction with the radio lobes produced by the AGN, displacing the surrounding X-ray gas (e.g. McNamara & Nulsen 2012; Barai et al. 2016; Yang, Gaspari & Marlow 2019; Gastaldello et al. 2021). It has been estimated that an energy of 1.5 × 1056 and $4\times 10^{57}\,{\rm erg}$ has been released by the most and second most recent outbursts, respectively, suggesting that the most recent outburst might still be ongoing. These features are correlated with the group’s observed radio emission (Giacintucci et al. 2011), and can serve as clear indicators of AGN feedback being present. Previous studies of the group have also found moderate turbulent velocities of ∼175 km s−1 and a 3D Mach number of the order of 0.4, using resonant scattering (e.g. de Plaa et al. 2012; Ogorzalek et al. 2017), further indicating the presence of such a mechanism. These characteristics make NGC 5813, a very promising candidate for the study of the effects AGN feedback can have on the distribution of elements in a low-mass system. Additionally, this target has some of the deepest Chandra data of any galaxy group and, similar to M49 has been found to have an explicit anticorrelation between its metal abundance and the location of its radio lobes (Randall et al. 2015). That work already suggests that this result is dependent on the Fe-bias; employing a two-temperature fit brings the abundance in the region of the extended radio lobes in better agreement to their surrounding medium, although the central region appears to remain under-enriched.
Citation: Tran et al. 2001
Citation function: Background; Background
The comparison with other hot corinos is not easy since we have a limited number of lines, in contrast to well-known sources that have been more extensively observed with ALMA and NOEMA, such as IRAS 16293-2422 (Jørgensen et al. 2016), NGC1333 IRAS 2A and 4A (Taquet et al. 2015; López-Sepulcre et al. 2017). In general, we find a similar inventory ofCOMs but with lower abundances in B1b-S. We are going to discuss only some trends and ratios between them. For example, one similarity with hot corinos are the higher abundances of O-bearing COMs with respect to N-bearing COMs. We observe a similar trend in B1b-S, where the highest abundances are obtained for CH3OCOH, CH3OCH3, and CH3CHO, while NH2CN and NH2CHO show the lowest abundances. Cyanamide has been recently detected towards the low-mass protostars IRAS 16293-2422 and NGC 1333 IRAS2A (Coutens et al. 2018), with observed NH2CN to NH2CHO ratios of 0.2and 0.02, respectively. These values are in the range of those observed towards the molecular clouds in the Galactic centre but lower than in Orion KL (Coutens et al. 2018). We obtain in B1b-S anabundance ratio of 0.25, similar to IRAS 16293-2422. Of the three possible isomers of C2 H4O2, we have detected CH3OCOH and CH2OHCHO. The observed CH3OCOH to CH2OHCHO ratio in B1b-S, ~20, is similar to that observed in the low-mass protostars in NGC 1333 and IRAS 16293-2422 (Taquet et al. 2015; Jørgensen et al. 2012). Acetic acid (CH3COOH) is the most stable but the least abundant of the three isomers (Lattelais et al. 2010). It has been observed in IRAS 16293-2422 with a ratio with respect to glycolaldehyde of ~11 (Jørgensen et al. 2016), consistent with the 5–15 upper limits in B1b-S. Glycolaldehyde and its corresponding alcohol, ethylene glycol, show similar abundances in B1b-S, slightly higher for CH2OHCHO. This is in contrast to other hot cores and hot corinos (Fuente et al. 2014; Jørgensen et al. 2016; Favre et al. 2017). However, since detections of these species are based on just a few lines, in particular for glycolaldehyde, column densities may be not well constrained and it is difficult to make definite conclusions. We have detected CH3CH2OCOH for the first time in a low-mass protostar, with a relatively high abundance of 10−11. This detection shows that the molecular complexity is high in young hot corinos and other species with a larger number of atoms could be present. It is noteworthy that this species has not been previously observed in the well-known hot corinos IRAS 16293-2422 and NGC 133IRAS4A. We have checked in the ALMA spectral line survey of IRAS 16293-2422 (PILS, Jørgensen et al. 2016), and no clear features are seen, although the observed frequencies are different. It is possible that the high level of line confusion and wide linewidths prevent the detection of weak lines in these more evolved sources.
Citation: Coutens et al. 2018
Citation function: Compare/Contrast
Over the past decade, direct measurements of the Hubble constant have achieved few percent in precision (Freedman 2017). Among the conducted measurements, the Supernova H0 for the Equation of State (SH0ES) team challenged the well-believed Hubble constant (H0) value inferred from the Planck cosmic microwave background (CMB) measurements assuming a flat Lambda cold dark matter (ΛCDM) model. In detail, the latest result from SH0ES is H0 = 74.03 ± 1.42 km s−1 Mpc−1 (Riess et al. 2019), which differs from thePlanck result H0 = 67.4 ± 0.5 km s−1 Mpc−1 by 4.4σ (Planck Collaboration VI 2018). Recently, the Carnegie-Chicago Hubble Program (CCHP) also presented a new and independent determination of H0 parameter based on a calibration of the Tip of the Red Giant Branch (TRGB) applied to Type Ia supernovae (SNIa) (Freedman et al. 2019, 2020). They find a value of H0 = 69.6 ± 2.5 km s−1Mpc−1, which is in the middle and consistent with the SH0ES and Planck values. A different analysis and calibration of the TRGB method was performed by the SH0ES team (Reid, Pesce & Riess 2019; Yuan et al. 2019) resulting in a slightly higher H0 value. To come to a robust conclusion, independent H0 probes with accuracy better than $2{{\ \rm per\ cent}}$ are crucial (Verde, Treu & Riess 2019). Among the possible independent probes, the time-delay strong lensing (TDSL) measurements, such as from the H0 Lenses in COSMOGRAIL’s Wellspring (H0LiCOW) collaboration (Bonvin et al. 2017; Suyu et al. 2017; Birrer et al. 2019; Wong et al. 2019), are the most precise to date. The latest constraint from a joint analysis of six gravitationally lensed quasars with measured time delays (Wong et al. 2019) indicates for a flat ΛCDM, $H_0=73.3^{+1.7}_{-1.8}$ km s−1 Mpc−1, a $2.4{{\ \rm per\ cent}}$ precision measurement, which are in agreement with local measurements from SNIa, but in 3.1σ tension with CMB. The forecasts of future 40 TDSL measurements suggest that the H0 would be constrained at $\mathcal {O}(1){{\ \rm per\ cent}}$ level (Shajib, Treu & Agnello 2018; Yildirim, Suyu & Halkola 2019). A more optimistic forecast for dark energy studies can be found in Shiralilou et al. (2019). On the other hand, one of the main obstacles for the lensing mass modelling, or to determine precise H0 value, is the mass-sheet degeneracy (Schneider & Sluse 2014; Xu et al. 2016). These issues in the H0LiCOW analysis have been frequently discussed in the literature (Sonnenfeld 2018; Kochanek 2019; Pandey, Raveri & Jain 2019). No direct evidence of bias or errors is found from a comparison of self-consistency among the individual lenses  (Millon et al. 2019; Liao et al. 2020). Considering the fact that both the Planck and H0LiCOW’s H0 values are based on general relativity (GR) plus ΛCDM model, it inspires us to question the concordance cosmology model and investigate the modified gravity (MG).
Citation: Verde, Treu & Riess 2019
Citation function: Motivation
During the X-ray ‘hard’ state, the radio and X-ray behaviour of BHXBs is correlated and has been studied in depth for many sources using quasi-simultaneous observations (e.g. Corbel et al. 2003; Gallo, Fender & Pooley 2003; Coriat et al. 2011; Corbel et al. 2013), and is known as the radio:X-ray plane. It was thought that all XBs followed a relation in the form of $L_{\rm Radio} \propto L_{\rm X-ray}^{0.6}$, based upon early observations of GX 339−4 (Hannikainen et al. 1998; Gallo et al. 2003; Corbel et al. 2003, 2013). This relation extends down to very low luminosities, i.e. into quiescence (Corbel et al. 2003, 2013; Plotkin et al. 2017; Tremou et al. 2020), and has been observed in other sources such as V404 Cygni (e.g. Corbel, Koerding & Kaaret 2008) and XTE J1118+480 (Gallo et al. 2014). However, further observations revealed the presence of another population of BHXBs which are less radio luminous than this relation, a so-called ‘radio-quiet’ branch, which followed $L_{\rm R} \propto L_{\rm X}^{1.4}$, such as H 1743−322 (e.g. Coriat et al. 2011; Williams et al. 2020). In some of these ‘radio-quiet’ objects, they are then found to re-join the ‘radio-loud’ branch when they go back into quiescence (Coriat et al. 2011; Carotenuto et al. 2021). The underlying cause of the split tracks (see Gallo, Miller & Fender 2012; Gallo et al. 2014; Gallo, Degenaar & van den Eijnden 2018, for a clustering analysis into the statistical robustness of this split) for BHXBs is not known, but it may be due to differences in the radiative efficiency of the accretion flow (Coriat et al. 2011; Koljonen & Russell 2019), an inclination effect of the source (Motta, Casella & Fender 2018), differences in the accretion disc contribution (Meyer-Hofmeister & Meyer 2014) or changes in the magnetic field (Casella & Pe’er 2009). For the purposes of this paper, we will refer to the original $L_{\rm R} \propto L_{\rm X}^{0.6}$ correlation sources as ‘radio-loud’ objects, and those that diverge on to the $L_{\rm R} \propto L_{\rm X}^{1.4}$ track as ‘radio-quiet’ sources.
Citation: Gallo et al. 2014
Citation function: Background; Background
The sample of DES RETs shows a preference for low-metallicity, strongly star-forming host environments. The PDF of their metallicities displays a strong similarity to the hosts of SESNe, as well as LGRBs. There is a clear difference to the PDF of SNe II, which follow SDSS field galaxies. The preference for low-metallicity systems is not as strong as for LGRBs or SLSNe, but the highest metallicities found in all three samples are very similar at around solar metallicity. This result is suggestive of a stripped-envelope, massive-star origin for RETs. The population of RET hosts lies, on average, between CCSNe and LGRBs/SLSNe in terms of both star formation and metallicity. A loose correlation exists between the luminosity and rarity of events, and the host galaxy conditions required for their formation − on average, rarer events occur in more extreme environments. The approximate rate of RETs (≥10−6 Mpc−3 yr−1; Drout et al. 2014; P18; Coppejans et al. 2020; Ho et al. 2020; Tampo et al. 2020, although the definition of RET varies in the above calculations) is ${\sim}1{{\ \rm per\ cent}}$ of the CCSN rate (Horiuchi et al. 2011; Li et al. 2011; Strolger et al. 2015), which itself is divided into the more common SNe II and sub-dominant SESNe (Kelly & Kirshner 2012; Frohmaier et al., submitted). At ${\sim}1{{\ \rm per\ cent}}$ of the CCSN rate, RETs are more common than SLSNe (${\sim}0.01{-}0.05{{\ \rm per\ cent}}$ of CCSNe; McCrum et al. 2015; Prajs et al. 2017; Frohmaier et al., in preparation) and LGRBs (intrinsically ${\sim}0.08{{\ \rm per\ cent}}$ when accounting for beaming; Graham & Schady 2016). These figures place the rate of DES RETs between extreme objects (SLSNe, LGRBs) and more common SNe (SNe II, SESNe) in terms of rate, matching the location of RET hosts in the various host galaxy parameter spaces presented in Section 5. While stressing rates are uncertain and host galaxy parameters span wide ranges for all transients, they are both linked to the respective transients’ progenitor channels. While it is likely that RETs are a heterogeneous population comprising several progenitor scenarios, it is reasonable to infer from the rates and the host properties that RETs are linked to very massive stars, potentially stripped of their envelopes, and possibly sharing some of the extreme properties of SLSN or LGRB progenitors such as rapid rotation and low metallicity. This hypothesis can be extended to posit that some RETs represent an intermediate and/or precursory step in the late stages of evolution of a massive star that is close to forming a SLSN or LGRB, whereby the initial collapse of the star occurs leading to shock breakout and subsequent cooling driving the RET light curve (P18), but the progenitor is sufficiently different to the progenitors of LGRBs and SLSNe such that the central engine either does not form or has properties that differ from the central engines of LGRBs or SLSNe, hence the lack of longer-term light curves.
Citation: Tampo et al. 2020
Citation function: Uses
Finally, we emphasize that although the parameter space covered by the DASH library is vast, it is by no means exhaustive. One obvious shortcoming, as discussed above, is that the DASH simulations are inadequate to describe major mergers with ${\cal M}\lesssim 100$. In those cases, dynamical friction due to the host, and self-friction due to tidally stripped material, cause the orbit of the subhalo to decay, exposing it to stronger tides. Another degree of freedom not covered here is the inner density slope of dark matter haloes. It is well known that observations of dwarf galaxies often suggest that their haloes have constant density cores, rather than the steep r−1-cusps predicted by dark matter-only simulations (e.g. Burkert 1995; Gentile et al. 2004; Oh et al. 2011; Hayashi & Chiba 2015). Such cores can be created within the CDM paradigm by a variety of baryonic processes (e.g. El-Zant, Shlosman & Hoffman 2001; Inoue & Saitoh 2011; Pontzen & Governato 2012; Ogiya & Mori 2014), and have a dramatic impact on the tidal evolution of subhaloes (Peñarrubia et al. 2010; Errani, Peñarrubia & Tormen 2015; Ogiya 2018). In addition, baryons modify the potentials of host- and subhaloes through the bulges and discs that they form at the halo centres, and these also strongly impact the tidal fields (Errani et al. 2017; Garrison-Kimmel et al. 2017). Finally, in the DASH simulations presented here, the host halo is assumed to be spherically symmetric, which allows us to completely specify each orbit with only two parameters (energy and angular momentum). Cosmological simulations, though, indicate that dark matter haloes are expected to be triaxial systems (e.g. Jing & Suto 2002; Allgood et al. 2006; Hayashi, Navarro & Springel 2007), consistent with the shapes of the gravitational potentials of galaxies and clusters as inferred from a variety of observations (e.g. Oguri et al. 2005; Corless & King 2007; Law & Majewski 2010). Triaxial systems have a much richer variety of orbits, which is likely to impact the tidal evolution of subhaloes.
Citation: Ogiya & Mori 2014
Citation function: Background