Datasets:
ReadingTimeMachine
/
rtm-sgt-ocr-v1

Dataset card Data Studio Files Community
2
source
stringlengths
1
2.05k
⌀
target
stringlengths
1
11.7k
Vollmeretal.(2005). put forward the role of ram pressure. combined with a tidal interaction. iu shaping the internal eas distribution. with its ;»=1 structure. and velocity field of NGC 1251.
\cite{vollmer05} put forward the role of ram pressure, combined with a tidal interaction, in shaping the internal gas distribution, with its $m=1$ structure, and velocity field of NGC 4254.
This partly explains why. in the imuermost regions. the detailed kinematics of the spiral preseuts some differences with that of our model which did not take iuto account the intracluster medi.
This partly explains why, in the innermost regions, the detailed kinematics of the spiral presents some differences with that of our model which did not take into account the intracluster medium.
More recently. Kauthariaetal.(2007) preseuted a low radio frequency continuum map of the galaxy which is best explained invoking a rai pressure scenario.
More recently, \cite{Kantharia07} presented a low radio frequency continuum map of the galaxy which is best explained invoking a ram pressure scenario.
However so far. its possible contribution ou the properties of the III bridge and VirgolII21 has uot vet been investigated.
However so far, its possible contribution on the properties of the HI bridge and VirgoHI21 has not yet been investigated.
The two above-mentioned papers do not claim that their orien is ranr-pressure. and indeed our pure tidal model is able to reproduce these features provided that the IIT disk was originally 10nch more exteuded than the optical radius an bypothesis which was not adopted in Vollmeretal. (2005).
The two above-mentioned papers do not claim that their origin is ram-pressure, and indeed our pure tidal model is able to reproduce these features provided that the HI disk was originally much more extended than the optical radius – an hypothesis which was not adopted in \cite{vollmer05}.
Showing that virgolII21 be a tidal debris taking the appearance of a dark galaxy docs not directly rule out the possibility that it is a real dark galaxw.
Showing that virgoHI21 be a tidal debris taking the appearance of a dark galaxy does not directly rule out the possibility that it is a real dark galaxy.
The dark galaxy hypothesis however suffers several difficulties nnexplained so far: These facts are naturally explained by the tidal scenario proposed for VirgolII21.
The dark galaxy hypothesis however suffers several difficulties unexplained so far: These facts are naturally explained by the tidal scenario proposed for VirgoHI21.
Whether they can also be addressed with the Dark Galaxy hypothesis reuais to be demonstrated. in particular with a muncerical iocdel.
Whether they can also be addressed with the Dark Galaxy hypothesis remains to be demonstrated, in particular with a numerical model.
Although challenged. the putative existence of Dark Calaxics as massive as VirgoIII21. has fostered a number of follow-up works.
Although challenged, the putative existence of Dark Galaxies as massive as VirgoHI21, has fostered a number of follow-up works.
As discussed by Karacheutsevetal.(2006) such invisible ghost objects should tidally perturb ealaxies in their ucighborlood. explaining why a fraction of apparently isolated spiral stellar disks seen to show sjeus of an external perturbation.
As discussed by \citet{karachentsev06} such invisible ghost objects should tidally perturb galaxies in their neighborhood, explaining why a fraction of apparently isolated spiral stellar disks seem to show signs of an external perturbation.
We note however that other mechanisms may account for them. such as accretion of diffuse eas (Bournaudetal.2005)..
We note however that other mechanisms may account for them, such as accretion of diffuse gas \citep{bournaud05m1}.
Using a seres of nunerical simulations. we have investigated the role of the initial inipact velocity in the formation of tidal tails during ealaxv-ealaxy collisions.
Using a series of numerical simulations, we have investigated the role of the initial impact velocity in the formation of tidal tails during galaxy-galaxy collisions.
This work was motivated bv the fact that collisional debris. which may become detached from their pareut ealaxies. exhibit many of the properties expected for the disputed class of "dark galaxies”. as initially suspected. anone others. by Bekki et al. (
This work was motivated by the fact that collisional debris, which may become detached from their parent galaxies, exhibit many of the properties expected for the disputed class of “dark galaxies", as initially suspected, among others, by Bekki et al. (
2005).
2005).
We found that. contrary to common belief. high-velocity fly-bvs at 1000 kan sL| or more can geucrate the development of strealus of tidal origin.
We found that, contrary to common belief, high-velocity fly-bys at 1000 km $^{-1}$ or more can generate the development of streams of tidal origin.
These tails are less massive thui those formed duriug lower-velocity encounters. but cau be as loue.
These tails are less massive than those formed during lower-velocity encounters, but can be as long.
An important difference is that tidal tails from higli-volocitv interactions contain a higher fraction ofeas and can even be devoid ofstars.
An important difference is that tidal tails from high-velocity interactions contain a higher fraction of gas and can even be devoid of stars.
Iudecd the internal stellar disk of the parcut galaxy is only weakly disturbed aud the tails are mostly formed from the external III disks.
Indeed the internal stellar disk of the parent galaxy is only weakly disturbed and the tails are mostly formed from the external HI disks.
This explains why the role of high-speed collisions has so far been neelected. except to account for the harassuient process m clusters of galaxies with repeated distaut interactions.
This explains why the role of high-speed collisions has so far been neglected, except to account for the harassment process in clusters of galaxies with repeated distant interactions.
Streamune motions are present in collisional debris and may generate in detached clouds velocity eracicuts conrparable to those expected for rotating. sclf&eravitatiug. bodies.
Streaming motions are present in collisional debris and may generate in detached clouds velocity gradients comparable to those expected for rotating, self-gravitating, bodies.
Starless eas clouds. showing apparent but fake sigus of rotation. are thus the natural by-product of high-velocity collisious.
Starless gas clouds, showing apparent but fake signs of rotation, are thus the natural by-product of high-velocity collisions.
Such characteristics are actually exactly those used to clefine an object asa Dark Galaxy candidate: an III detection. without auv stellar counterpart. aud with a kinematics racing the presence of a massive dark matter halo.
Such characteristics are actually exactly those used to define an object as a Dark Galaxy candidate: an HI detection, without any stellar counterpart, and with a kinematics tracing the presence of a massive dark matter halo.
A candidate Dark Galaxy that las receutlv attracted uuch attention is VirgolII21: au HII cloud in the Vireo Cluster. apparently connected by a faint III bridge to he spiral ealaxy NGC 1251. aud. exhibiting a strong velocity eradieut of 200 kan + attributed to a dark uatter halo as massive as LOM ML. (Minelün et al.
A candidate Dark Galaxy that has recently attracted much attention is VirgoHI21: an HI cloud in the Virgo Cluster, apparently connected by a faint HI bridge to the spiral galaxy NGC 4254, and exhibiting a strong velocity gradient of 200 km $^{-1}$ attributed to a dark matter halo as massive as $^{11}$ $_{\sun}$ (Minchin et al.
2007).
2007).
We propose here that this intriguiug III structure results simply from a high-volocitv collision. a comunuon phenomenon dn clusters of galaxies.
We propose here that this intriguing HI structure results simply from a high-velocity collision, a common phenomenon in clusters of galaxies.
Our umuerical sinuulation reproduces the morphology aud kinematics of the whole system. including the pareut spiral galaxy. odieved to be NGC 1251. the TD bridge. aud the VireollI21 cloud.
Our numerical simulation reproduces the morphology and kinematics of the whole system, including the parent spiral galaxy, believed to be NGC 4254, the HI bridge, and the VirgoHI21 cloud.
A counter-tidal tail was formed too. mt was shorter aud has now fallen back outo the arent spiral galaxy. explaining the present sinele-tailed uorphologv of NGC 1251.
A counter-tidal tail was formed too, but was shorter and has now fallen back onto the parent spiral galaxy, explaining the present single-tailed morphology of NGC 4254.
This model assumes that the interaction occurred 750 Myr ago with a massive galaxy. rowadavs line LOO kpe away in projected distance.
This model assumes that the interaction occurred 750 Myr ago with a massive galaxy, nowadays lying 400 kpc away in projected distance.
A candidate for the iterloper is the spiral NGC L192 but other galaxies/orbits are probably possible too. secu the aree uuniber of massive galaxies within 1 Alpe is this region.
A candidate for the interloper is the spiral NGC 4192 but other galaxies/orbits are probably possible too, seen the large number of massive galaxies within 1 Mpc is this region.
The concerns raised by Πιο et al. (
The concerns raised by Minchin et al. (
2007) against the tidal scenario were all addressed.
2007) against the tidal scenario were all addressed.
With the availability of deep III survevs. the number
With the availability of deep HI surveys, the number
QSO SBS 0909|532. Mecdiavilla et al. (
QSO SBS 0909+532, Mediavilla et al. (
2005) found cilferential extinction of both the CIER anc BLER. as well as achromatic microlensing of the CER.
2005) found differential extinction of both the CER and BLER as well as achromatic microlensing of the CER.
We conclude that spectroscopic observations of the first. gravitationally lensed. quasar provide. valuable information on the structure of the main lens (cD) galaxy at 2 = 0.36.
We conclude that spectroscopic observations of the first gravitationally lensed quasar provide valuable information on the structure of the main lens (cD) galaxy at $z$ = 0.36.
The data support the existence of a dark halo that mainly. consists of non-collapsed material. rather than a granular dark halo harbouring a significant population of collapsed objects.
The data support the existence of a dark halo that mainly consists of non-collapsed material, rather than a granular dark halo harbouring a significant population of collapsed objects.
The dark halo probably includes compact dusty clouds of gas with projected (into the source plane) radial sizes verifving the constrain Regn<PossRete.
The dark halo probably includes compact dusty clouds of gas with projected (into the source plane) radial sizes verifying the constraint $R_{CER} < R_{cloud} < R_{BLER}$.
For example. a tvpical radius Repos7102 pe is in agreement with measurements of Acgg and 2g;gg of quasars (e... Yonehara 2001: Ixaspi et al.
For example, a typical radius $R_{cloud} \approx 10^{-2}$ pc is in agreement with measurements of $R_{CER}$ and $R_{BLER}$ of quasars (e.g., Yonehara 2001; Kaspi et al.
2000).
2000).
Phe clouds must also be sullicienthy dilfuse that they do no appreciably gravitationally microlens the quasar light (o... Ixerins. Binney Silk 2002).
The clouds must also be sufficiently diffuse that they do not appreciably gravitationally microlens the quasar light (e.g., Kerins, Binney Silk 2002).
In this paper we consider a network of clouds of similar composition.
In this paper we consider a network of clouds of similar composition.
However. a more complicated scenario incorporating cillerent kinds of dust cannot be rulec out (e.g... AleGough et al.
However, a more complicated scenario incorporating different kinds of dust cannot be ruled out (e.g., McGough et al.
2005).
2005).
Previous spectroscopic studies of the internal region of the eD galaxy suggested the possible existence of a central massive dark object (Meciavilla et al.
Previous spectroscopic studies of the internal region of the cD galaxy suggested the possible existence of a central massive dark object (Mediavilla et al.
2000). so that the new results from HIST.STIS spectra of the quasar images (crossing the galaxy halo) complement the previous information on the galaxy nucleus.
2000), so that the new results from HST–STIS spectra of the quasar images (crossing the galaxy halo) complement the previous information on the galaxy nucleus.
We thank P. Goudfrooij for helpful comments on the CALSTIS pipeline software.
We thank P. Goudfrooij for helpful comments on the CALSTIS pipeline software.
Ajased on observations made with the NASA/ESA Llubble Space "Telescope. obtained from the data archive at the Space Telescope Science Institute.
Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute.
STSclL is operated by the Association of Universities for Research in Astronomy. Inc. under NASA contract NAS 5-26555.
STScI is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS 5-26555.
"his work was supported by Universidad de Cantabria funds and the MOVE erant. AYA2004-08243-C'03-02.
This work was supported by Universidad de Cantabria funds and the MCyT grant AYA2004-08243-C03-02.
gas in a galaxy is dominated byHi, then we can use the KS law to express the SFR surface density as UsrrοςXj, where ?) gives the power law index 6 a value of 1.44-0.15.
gas in a galaxy is dominated by, then we can use the KS law to express the SFR surface density as $\Sigma_{\rm SFR} \propto \Sigma_{\rm HI}^{\beta}$, where \citet{1998ARA&A..36..189K} gives the power law index $\beta$ a value of $1.4 \pm 0.15$.
Eliminating Xsrn, we get theHI surface density as weοςR*-9/8,
Eliminating $\Sigma_{\rm SFR}$, we get the surface density as $\Sigma_{\rm HI}^\beta \propto R^{(5\gamma-6)/8}$.
Integrating the surface density over the size of the galaxy, we get Expressing this as a function of the surface area, we get where Ca is a constant of proportionality.
Integrating the surface density over the size of the galaxy, we get Expressing this as a function of the surface area, we get where $C_{\rm A}$ is a constant of proportionality.
This generalizes the result (MreΑἱ15 for Newtonian gravity and KS law slope of 1.4) from ?) to arbitrary KS law slopes and generalized effective gravitational force laws.
This generalizes the result $M_{\rm HI} \propto A^{1.18}$ for Newtonian gravity and KS law slope of 1.4) from \citet{2011ApJ...732..105C} to arbitrary KS law slopes and generalized effective gravitational force laws.
?) have shown that such a relation depends only weakly on the metallicity of the galaxy.
\citet{2011PhRvL.106v1301K} have shown that such a relation depends only weakly on the metallicity of the galaxy.
The power law relates the mass of a galaxy to its size and can be directly compared to the data (See Fig. 1)).
The power law relates the mass of a galaxy to its size and can be directly compared to the data (See Fig. \ref{fig:mvsa}) ).
We can now use the scaling in Eqn.
We can now use the scaling in Eqn.
2 between V and R to find Mg; as a function of the galaxy size.
\ref{vr} between $V$ and $R$ to find $M_{\rm HI}$ as a function of the galaxy size.
This gives us the mass as where Ον is another constant of proportionality.
This gives us the mass as where $C_{\rm V}$ is another constant of proportionality.
This shows that the observed slope of the HITF relation is a probe of both the KS law and the law of gravity.
This shows that the observed slope of the HITF relation is a probe of both the KS law and the law of gravity.
For Newtonian gravity and KS law slope of 1.4 we have Mmi:«y?36
For Newtonian gravity and KS law slope of 1.4 we have $M_{\rm HI} \propto V^{2.36}$.
This can now be compared directly with the data (See Fig. 2)),
This can now be compared directly with the data (See Fig. \ref{fig:hitf}) ),
but à prior knowledge of the KS law slope will be required to determine the effective gravitational force law.
but a prior knowledge of the KS law slope will be required to determine the effective gravitational force law.
This shortcoming can be overcome by simultaneously comparing Eqn.
This shortcoming can be overcome by simultaneously comparing Eqn.
6 to the HITF data and Eqn.
\ref{eq:MV} to the HITF data and Eqn.
5 to the mass vs area data.
\ref{eq:MA} to the mass vs area data.
The ratio of the two slopes isa function of y, but independent of 8.
The ratio of the two slopes isa function of $\gamma$, but independent of $\beta$.
Hence, determining both slopes from observations can break the y— degeneracy and determine irrespective of our prior knowledge of 8.
Hence, determining both slopes from observations can break the $\gamma-\beta$ degeneracy and determine $\gamma$ irrespective of our prior knowledge of $\beta$.
Being able to explain¥ both observed relations for plausible values of these parameters is a crucial reality check for our model.
Being able to explain both observed relations for plausible values of these parameters is a crucial reality check for our model.
The Arecibo Dual-Beam Survey (7) (ADBS) has conducted a “blind” survey of ~ 430 deg? of sky and detected the signal in 265 galaxies.
The Arecibo Dual-Beam Survey \citep{2000ApJS..130..177R} (ADBS) has conducted a “blind” survey of $\sim$ 430 $^2$ of sky and detected the signal in 265 galaxies.
Interferometric mapping of 84 galaxies was carried out with the NRAO’s Very Large Array (VLA) as most of the ADBS galaxies were unresolved at the resolution of the Arecibo.
Interferometric mapping of 84 galaxies was carried out with the NRAO's Very Large Array (VLA) as most of the ADBS galaxies were unresolved at the resolution of the Arecibo.
Accurate sizes of 50 of them were compiled by ?) to tabulate Mur and A cross section with column density above 2x1035 οπι3) of individual ADBS galaxies.
Accurate sizes of 50 of them were compiled by \citet{2003ApJ...585..256R} to tabulate $M_{\rm HI}$ and $A$ cross section with column density above $2\times10^{20} \ {\rm cm^{-2}}$ ) of individual ADBS galaxies.
The observed sizes span 3 orders of magnitude (0.5>log(A/kpc?) 3.5) and provide the data for the mass vs area relation.
The observed sizes span 3 orders of magnitude $0.5>{\rm log}(A/{\rm kpc^2})>3.5$ ) and provide the data for the mass vs area relation.
For the following analysis, we have used only objects with large projected areas (log(.A/kpc?)> 2) as the smaller galaxies may have systematically uncertain sizes limited by the resolution of the present surveys.
For the following analysis, we have used only objects with large projected areas ${\rm log}(A/{\rm kpc^2})>2$ ) as the smaller galaxies may have systematically uncertain sizes limited by the resolution of the present surveys.
Fig.
Fig.
1 presents the observed data and compares it with the fiducial models.
\ref{fig:mvsa} presents the observed data and compares it with the fiducial models.
?) presented a sample of local (D<60 Mpc) field galaxies with accurate 21 cm observations to construct a BTF relation.
\citet{2010AJ....140..663G} presented a sample of local $D<60$ Mpc) field galaxies with accurate 21 cm observations to construct a BTF relation.
We select the galaxies listed by ?) and used by ?)..
We select the galaxies listed by \citet{2000ApJ...529..698S} and used by \citet{2010AJ....140..663G}.
All these galaxies have accurate Cepheid distances (?) determined using theTelescope Ho Key Project and 21 cm Arecibo observations from ?)..
All these galaxies have accurate Cepheid distances \citep{2000ApJ...529..698S} determined using the $H_0$ Key Project and 21 cm Arecibo observations from \citet{1997AJ....113...53G}.
For all these galaxies we use Mui and Woo (the width at which the profile drops to of its maximum value) as listed by ?),, inclination corrected following the method of ?)..
For all these galaxies we use $M_{\rm HI}$ and $W_{20}$ (the width at which the profile drops to of its maximum value) as listed by \citet{2010AJ....140..663G}, inclination corrected following the method of \citet{1997AJ....113...53G}.
Following ?) this is commonly used as a proxy for rotation velocity in radio astronomy ?.
Following \citet{1977A&A....54..661T} this is commonly used as a proxy for rotation velocity in radio astronomy .
. This provides the data for the high mass range in the HITF relation.
This provides the data for the high mass range in the HITF relation.
'To accurately determine the slope of the HITF relation, this catalogue needs to be supplemented with data on low
To accurately determine the slope of the HITF relation, this catalogue needs to be supplemented with data on low
concludes when type Ia supernovae begin.
concludes when type Ia supernovae begin.
The la SNe drive an overall expansion of the cluster. causing stars at large radii (primarily first-generation stars) to dissociate from the cluster. thereby reducing the ratio of first- to second-generation stars to present-day levels.
The Ia SNe drive an overall expansion of the cluster, causing stars at large radii (primarily first-generation stars) to dissociate from the cluster, thereby reducing the ratio of first- to second-generation stars to present-day levels.
AGB stars are also the source of chemical differences between the first and second generation in. the model of ?.. but their nodel involves a significant amount of gas being acereted from the environment. reducing the mass required for the first generation of stars.
AGB stars are also the source of chemical differences between the first and second generation in the model of , but their model involves a significant amount of gas being accreted from the environment, reducing the mass required for the first generation of stars.
The authors investigate the mass-aceretion rate for proto-globular clusters in a variety of cosmological environments. and conclude that clusters with initial masses above 10'M.. would have been able to accrete significant amounts of gas in the early Milky Way.
The authors investigate the mass-accretion rate for proto-globular clusters in a variety of cosmological environments, and conclude that clusters with initial masses above $10^{4}{\rm M_{\odot}}$ would have been able to accrete significant amounts of gas in the early Milky Way.
They also calculate that the ninimum mass for sufficient gas aceretion would be lower for globular clusters forming as satellites of dwarf galaxies. a claim that could be tested with observations of intermediate-age star clusters in the Large Magellanic Cloud (LMC).
They also calculate that the minimum mass for sufficient gas accretion would be lower for globular clusters forming as satellites of dwarf galaxies, a claim that could be tested with observations of intermediate-age star clusters in the Large Magellanic Cloud (LMC).
Interestingly. the recent high-resolution study of finds no sign of light-element anticorrelations among 14 red giant stars in the massive intermediate-age LMC cluster NGC 1866.
Interestingly, the recent high-resolution study of finds no sign of light-element anticorrelations among 14 red giant stars in the massive intermediate-age LMC cluster NGC 1866.
The authors suggest that the minimum mass for enrichment in the LMC is on the order of 10°M...
The authors suggest that the minimum mass for self-enrichment in the LMC is on the order of $10^{5}{\rm M_{\odot}}$.
Although there are questions about the likelihood that early globular clusters would accrete unprocessed gas from their surroundings with precisely the right metallicity (e.g... Martell 2011)). and the gas dynamics involved in mass loss and dilution in globular clusters have been the subject of few advanced numerical studies (e.g.. Priestley et al. 2
Although there are questions about the likelihood that early globular clusters would accrete unprocessed gas from their surroundings with precisely the right metallicity (e.g., Martell ), and the gas dynamics involved in mass loss and dilution in globular clusters have been the subject of few advanced numerical studies (e.g., Priestley et al. ;
011:: D'Ercole et al. 2011))
D'Ercole et al. ),
. the model provides an important discussion of the interplay between early cluster self-enrichment and the galaxy-scale environment.
the model provides an important discussion of the interplay between early cluster self-enrichment and the galaxy-scale environment.
These scenarios rely implicitly on the high mass and high density of early globular clusters to retain and/or accrete gas well enough to permit a second burst of star formation.
These scenarios rely implicitly on the high mass and high density of early globular clusters to retain and/or accrete gas well enough to permit a second burst of star formation.
It is therefore not surprising that although stars with second-generation-like light-element abundances are found in every globular cluster in the Milky Way. they are not found at all in old open clusters.
It is therefore not surprising that although stars with second-generation-like light-element abundances are found in every globular cluster in the Milky Way, they are not found at all in old open clusters.
In studies of individual stars (e.g.. Jacobson et al.2
In studies of individual stars (e.g., Jacobson et al.;
008:: Martell Smith 2009)) and mean abundances (e.g.. de Silva et al. 2009)
Martell Smith ) and mean abundances (e.g., de Silva et al. )
) for old open clusters. light-element abundance behavior is found to be distinctly different from what is observed in globular clusters.
for old open clusters, light-element abundance behavior is found to be distinctly different from what is observed in globular clusters.
They are also quite to have formed in the halo field. but they have recently been found =there: (hereafter MGIO) searched the SEGUE survey (Sloan Extension for Galactic Understanding and Exploration. Yanny et al. 2009)
They are also quite to have formed in the halo field, but they have recently been found there: (hereafter MG10) searched the SEGUE survey (Sloan Extension for Galactic Understanding and Exploration, Yanny et al. )
) for halo giants with unusually strong UV/blue CN bands and identified 49 (of roughly 2000) stars likely to have low carbon abundances and high nitrogen abundances.
for halo giants with unusually strong UV/blue CN bands and identified $49$ (of roughly $2000$ ) stars likely to have low carbon abundances and high nitrogen abundances.
Similarly. compiled a sample of 144. metal-poor disk. halo and bulge stars from the literature and identified 2 of those as Na-rich and likely to have originated in. globular clusters.
Similarly, compiled a sample of 144 metal-poor disk, halo and bulge stars from the literature and identified 2 of those as Na-rich and likely to have originated in globular clusters.