Local Group dwarf spheroidal satellite galaxies are the faintest extragalactic stellar systems known. We examine recent data for these objects in the plane of the Baryonic Tully-Fisher Relation (BTFR). While some dwarf spheroidals adhere to the BTFR, others deviate substantially. We examine the residuals from the BTFR and find that they are not random. The residuals correlate with luminosity, size, metallicity, ellipticity, and susceptibility of the dwarfs to tidal disruption in the sense that fainter, more elliptical, and tidally more susceptible dwarfs deviate farther from the BTFR. These correlations disfavor stochastic processes and suggest a role for tidal effects. We identify a test to distinguish between the ΛCDM and MOND based on the orbits of the dwarf satellites of the Milky Way and how stars are lost from them.
In this work, we studied the stellar and baryonic Tully-Fisher relations by using hydrodynamical simulations in a cosmological framework. We found that supernova feedback plays an important role on shaping the stellar Tully-Fisher relation causing a steepening of its slope at the low-mass end, consistently with observations. The bend of the relation occurs at a characteristic velocity of approximately 100 km/s, in concordance with previous observational and theoretical findings. With respect to the baryonic Tully-Fisher relation, the model predicts a linear trend at z~0 with a weaker tendency …
We calibrate the Baryonic Tully-Fisher (BTF) Relation using a sample of gas dominated galaxies. These determine the absolute scale of the baryonic mass--rotation speed relation independent of the choice of stellar mass estimator. We find a BTF slope of 3.94 +/- 0.07 (random) +/- 0.08 (systematic) and a zero point of 1.79 +/- 0.26 (random) +/- 0.25 (systematic). We apply this relation to estimate the stellar masses of star dominated galaxies. This procedure reproduces the trend of mass-to-light ratio with color predicted by population synthesis models. The normalization is also correct, consist…
We studied, for the first time, the near infrared, stellar and baryonic Tully-Fisher relations for a sample of field galaxies taken from an homogeneous Fabry-Perot sample of galaxies (the GHASP survey). The main advantage of GHASP over other samples is that maximum rotational velocities were estimated from 2D velocity fields, avoiding assumptions about the inclination and position angle of the galaxies. By combining these data with 2MASS photometry, optical colors, HI masses and different mass-to-light ratio estimators, we found a slope of 4.48\pm0.38 and 3.64\pm0.28 for the stellar and baryon…
Scaling relations are salient ingredients of galaxy evolution and formation models. I summarize results from the IMAGES survey, which combines spatially-resolved kinematics from FLAMES/GIRAFFE with imaging from HST/ACS and other facilities. Specifically, I will focus on the evolution of the stellar mass and baryonic Tully-Fisher Relations (TFR) from z=0.6 down to z=0. We found a significant evolution in zero point and scatter of the stellar mass TFR compared to the local Universe. Combined with gas fractions derived by inverting the Schmidt-Kennicutt relation, we derived for the first time a b…
We present the results of a baryonic Tully-Fisher relation (BTFR) study for a local sample of relatively isolated disk galaxies. We derive a BTFR with a slope near 3 measured over about 4 dex in baryon mass for our combined \textrm{H\,\scriptsize{I}} and bright spiral disk samples. This BTFR is significantly flatter and has less scatter than the TFR (stellar mass only) with its slope near 4 reported for other samples and studies. A BTFR slope near 3 is in better agreement with the expected slope from simple $Λ$CDM cosmological simulations that include both stellar and gas baryons. The scatter …
The baryonic Tully-Fisher relation (BTF) is a fundamental relation between baryonic mass and maximum rotation velocity. It can be used to estimate distances, as well as to constrain the properties of dark matter and its relation with the visible matter. In this paper, we explore if extremely low-mass dwarf galaxies follow the same BTF relation as high-mass galaxies. We quantify the scatter in the BTF relation and use this to constrain the allowed elongations of dark matter halo potentials. We obtained HI synthesis data of 11 dwarf galaxies and derive several independent estimates for the maxim…
The Baryonic Tully-Fisher Relation (BTFR) is an empirical relation between baryonic mass and rotation velocity in disk galaxies. It provides tests of galaxy formation models in LCDM and of alternative theories like MOND. Observations of gas rich galaxies provide a measure of the slope and normalization of the BTFR that is more accurate (if less precise) than that provided by star dominated spirals, as their masses are insensitive to the details of stellar population modeling. Recent independent data for such galaxies are consistent with Mb = AVf^4 with A = 47+/-6 Msun (km/s)^-4. This is equiva…
We explore the use of the baryonic Tully-Fisher relation (bTFR) as a new distance indicator. Advances in near-IR imaging and stellar population models, plus precise rotation curves, have reduced the scatter in the bTFR such that distance is the dominant source of uncertainty. Using 50 galaxies with accurate distances from Cepheids or tip magnitude of the red giant branch, we calibrate the bTFR on a scale independent of $H_o$. We then apply this calibrated bTFR to 95 independent galaxies from the SPARC sample, using CosmicFlows-3 velocities, to deduce the local value of $H_o$. We find $H_o$ = 7…
[abr.] Using the multi-integral-field spectrograph GIRAFFE at VLT, we previsouly derived the stellar-mass Tully-Fisher Relation (smTFR) at z~0.6, and found that the distant relation is systematically offset by roughly a factor of two toward lower masses. We extend the study of the evolution of the TFR by establishing the first distant baryonic TFR. To derive gas masses in distant galaxies, we estimate a gas radius and invert the Schmidt-Kennicutt law between star formation rate and gas surface densities. We find that gas extends farther out than the UV light from young stars, a median of ~30%.…
Recent observational results found a bend in the Tully-Fisher Relation in such a way that low mass systems lay below the linear relation described by more massive galaxies. We intend to investigate the origin of the observed features in the stellar and baryonic Tully-Fisher relations and analyse the role played by galactic outflows on their determination. Cosmological hydrodynamical simulations which include Supernova feedback were performed in order to follow the dynamical evolution of galaxies. We found that Supernova feedback is a fundamental process in order to reproduce the observed trend…
A recent work (arXiv:2104.14481) has found a statistically significant transition in the Baryonic Tully-Fisher relation (BTFR) using low redshift data ($z<0.1$), with the transitions occurring at about 9 and 17 Mpc. Motivated by this finding, we carry out a variant of this analysis by fitting the data to an augmented BTFR, where both the exponent as well as normalization constant vary as a function of distance. We find that both the exponent and normalization constant show only a marginal variation with distance, and are consistent with a constant value, to within $2σ$. We also checked to see …
We study the gas kinematics traced by the 21-cm emission of a sample of six HI$-$rich low surface brightness galaxies classified as ultra-diffuse galaxies (UDGs). Using the 3D kinematic modelling code $\mathrm{^{3D}}$Barolo we derive robust circular velocities, revealing a startling feature: HI$-$rich UDGs are clear outliers from the baryonic Tully-Fisher relation, with circular velocities much lower than galaxies with similar baryonic mass. Notably, the baryon fraction of our UDG sample is consistent with the cosmological value: these UDGs are compatible with having no "missing baryons" withi…
We used K-band photometry, maximum rotational velocities derived from Fabry-Perot data and HI observed and predicted masses to study, for the first time, the K-band, stellar and baryonic Tully-Fisher relations for galaxies in Hickson compact groups. We compared these relations with the ones defined for galaxies in less dense environments from the GHASP survey and from a sample of gas-rich galaxies. We find that most of the Hickson compact group galaxies lie on the K-band Tully-Fisher relation defined by field galaxies with a few low-mass outliers, namely HCG 49b and HCG 96c, which appear to ha…
The baryonic Tully-Fisher relation as an independent direct probe of cosmology and of the nature of dark matter
Institute for Fundamental Physics of the Universe (IFPU)（宇宙基础物理研究所）；SISSA - International School for Advanced Studies（SISSA - 国际高等研究院）；INAF - Osservatorio Astronomico di Trieste（意大利国家天体物理研究所 - 的里雅斯特天文台）；INFN – National Institute for Nuclear Physics（意大利国家核物理研究所）
The scaling of disk galaxy rotation velocity with baryonic mass (the "Baryonic Tully-Fisher" relation, BTF) has long confounded galaxy formation models. It is steeper than the M ~ V^3 scaling relating halo virial masses and circular velocities and its zero point implies that galaxies comprise a very small fraction of available baryons. Such low galaxy formation efficiencies may in principle be explained by winds driven by evolving stars, but the tightness of the BTF relation argues against the substantial scatter expected from such vigorous feedback mechanism. We use the APOSTLE/EAGLE simulati…
The Baryonic Tully-Fisher relation (BTFR) is a clear manifestation of the underlying physics of galaxy formation. As such, it is used to constrain and test galaxy formation and evolution models. Of particular interest, apart from the slope of the relation, is its intrinsic scatter. In this paper, we use the EAGLE simulation to study the dependence of the BTFR on the size of the simulated galaxy sample. The huge number of datapoint available in the simulation is indeed not available with current observations. Observational studies that computed the BTFR used various (small) size samples with th…
We study the baryonic Tully-Fisher relation (BTFR) at z=0 using 153 galaxies from the SPARC sample. We consider different definitions of the characteristic velocity from HI and H-alpha rotation curves, as well as HI line-widths from single-dish observations. We reach the following results: (1) The tightest BTFR is given by the mean velocity along the flat part of the rotation curve. The orthogonal intrinsic scatter is extremely small (6%) and the best-fit slope is 3.85+/-0.09, but systematic uncertainties may drive the slope from 3.5 to 4.0. Other velocity definitions lead to BTFRs with system…
Most of the baryons in the Universe are not in the form of stars and cold gas in galaxies. Galactic outflows driven by supernovae/stellar winds are the leading mechanism for explaining this fact. The scaling relation between galaxy mass and outer rotation velocity (also known as the baryonic Tully-Fisher relation, BTF) has recently been used as evidence against this viewpoint. We use a LCDM based semi-analytic disk galaxy formation model to investigate these claims. In our model, galaxies with less efficient star formation and higher gas fractions are more efficient at ejecting gas from galaxi…
Providing a theoretical basis for the baryonic Tully-Fisher Relation (BTFR; baryonic mass vs rotational velocity in spiral galaxies) in the LCDM paradigm has proved problematic. Simple calculations suggest too low a slope and too high a scatter, and recent semi-analytic models and numerical galaxy simulations typically fail to reproduce some aspects of the relation. Furthermore, the assumptions underlying one model are often inconsistent with those behind another. This paper aims to develop a rigorous prediction for the BTFR in the context of LCDM, using only a priori expected effects and rela…
We use high resolution cosmological simulations of Milky Way-mass galaxies that include both baryons and dark matter to show that baryonic physics (energetic feedback from supernovae and subsequent tidal stripping) significantly reduces the dark matter mass in the central regions of luminous satellite galaxies. The reduced central masses of the simulated satellites reproduce the observed internal dynamics of Milky Way and M31 satellites as a function of luminosity. We use these realistic satellites to update predictions for the observed velocity and luminosity functions of satellites around Mi…
The baryonic Tully-Fisher relation is an important observational constraint on cosmological and galactic models. However, it is critical to keep in mind that in observations only stars, molecular, and atomic gas are counted, while the contribution of the ionized gas is almost universally missed. The ionized gas is, however, expected to be present in the gaseous disks of dwarf galaxies simply because they are exposed to the cosmic ionizing background and to the stellar radiation that manages to escape from the central regions of the galactic disks into their outer layers. Such an expectation is…
We combine data from the Spitzer Survey for Stellar Structure in Galaxies (S$^4$G), a recently calibrated empirical stellar mass estimator from Eskew et al., and an extensive database of HI spectral line profiles to examine the baryonic Tully-Fisher (BTF) relation. We find 1) that the BTF has lower scatter than the classic Tully-Fisher (TF) relation and is better described as a linear relationship, confirming similar previous results, 2) that the inclusion of a radial scale in the BTF decreases the scatter but only modestly, as seen previously for the TF relation, and 3) that the slope of the …
We analyse the Tully-Fisher relation at moderate redshift from the point of view of the underlying stellar populations, by comparing optical and NIR photometry with a phenomenological model that combines population synthesis with a simple prescription for chemical enrichment. The sample comprises 108 late-type galaxies extracted from the FORS Deep Field (FDF) and William Herschel Deep Field (WHDF) surveys at z<1 (median redshift z=0.45). A correlation is found between stellar mass and the parameters that describe the star formation history, with massive galaxies forming their populations early…
We study different incarnations of the Tully-Fisher (TF) relation for the Local Volume (LV) galaxies taken from Updated Nearby Galaxy Catalog. The UNGC sample contains 656 galaxies with $W_{50}$ HI-line-width estimates, mostly belonging to low mass dwarfs. Of them, 296 objects have distances measured with accuracy better than 10%. For the sample of 331 LV galaxies having baryonic masses $\log M_{bar} > 5.8 \log M_\odot$ we obtain a relation $\log M_{bar}= 2.49 \log W_{50} + 3.97$ with observed scatter of 0.38 dex. The largest factors affecting the scatter are observational errors in $K$-band m…
An acceleration scale of order $10^{-10}\mathrm{m/s^2}$ is implicit in the baryonic Tully-Fisher and baryonic Faber-Jackson relations, independently of any theoretical preference or bias. We show that the existence of this scale in the baryonic Faber-Jackson relation is most apparent when data from pressure supported systems of vastly different scales including globular clusters, elliptical galaxies, and galaxy clusters are analyzed together. This suggests the relevance of the acceleration scale $10^{-10}\mathrm{m/s^2}$ to structure formation processes at many different length scales and could…
Recent observational and theoretical works have suggested that the Tully-Fisher Relation might be generalised to include dispersion-dominated systems by combining the rotation and dispersion velocity in the definition of the kinematical indicator. Mergers and interactions have been pointed out as responsible of driving turbulent and disordered gas kinematics, which could generate Tully-Fisher Relation outliers. We intend to investigate the gas kinematics of galaxies by using a simulated sample which includes both, gas disc-dominated and spheroid-dominated systems. Cosmological hydrodynamical s…
Power-law relations between tracers of baryonic mass and rotational velocities of disk galaxies, so-called Tully-Fisher relations (TFRs), offer a wealth of applications in galaxy evolution and cosmology. However, measurements of rotational velocities require galaxy inclinations, which are difficult to measure, thus limiting the range of TFR studies. This work introduces a maximum likelihood estimation (MLE) method for recovering the TFR in galaxy samples with limited or no information on inclinations. The robustness and accuracy of this method is demonstrated using virtual and real galaxy samp…
In this paper we combine high resolution N-body simulations with a semi analytical model of galaxy formation to study the effects of a possible Warm Dark Matter (WDM) component on the observable properties of galaxies. We compare three WDM models with a dark matter mass of 0.5, 0.75 and 2.0 keV, with the standard Cold Dark Matter case. For a fixed set of parameters describing the baryonic physics the WDM models predict less galaxies at low (stellar) masses, as expected due to the suppression of power on small scales, while no substantial difference is found at the high mass end. However these …
Dwarf spheroidal galaxies (dSphs) are extremely gas-poor, dark matter-dominated galaxies, which make them ideal to test the predictions of the cold dark matter (CDM) model. We argue that the removal of the baryonic component from gas-rich dwarf irregular galaxies, the progenitors of dSphs, can substantially reduce their central density. Thus, it may play an important role in alleviating one of the problems of the CDM model related to the structure of relatively massive satellite galaxies of the Milky Way (MW). Traditionally, collisionless cosmological N-body simulations are used when confronti…
Radio galaxies with bent jets are predominantly located in groups and clusters of galaxies. We use bent-double radio sources, under the assumption that their jets are bent by ram-pressure, to probe intragroup medium (IGM) gas densities in galaxy groups. This method provides a direct measurement of the intergalactic gas density and allows us to probe IGM gas at large radii and in systems whose IGM is too cool to be detected by the current generation of X-ray telescopes. We find gas with densities of 10^(-3)-10^(-4) per cubic centimeter at group radii from 15-700 kpc. A rough estimate of the tot…
We present a SINFONI integral field kinematical study of 33 galaxies at z~3 from the AMAZE and LSD projects which are aimed at studying metallicity and dynamics of high-redshift galaxies. The number of galaxies analyzed in this paper constitutes a significant improvement compared to existing data in the literature and this is the first time that a dynamical analysis is obtained for a relatively large sample of galaxies at z~3. 11 galaxies show ordered rotational motions (~30% of the sample), in these cases we estimate dynamical masses by modeling the gas kinematics with rotating disks and expo…
The mass--velocity--size relation of late-type galaxies decouples into independent correlations between mass and velocity (the Tully-Fisher relation), and between mass and size. This behaviour is different to early-type galaxies which lie on a Fundamental Plane. We study the coupling of the Tully-Fisher and mass-size relations in observations (the SPARC sample) and in empirical galaxy formation models based on halo abundance matching, and rotation curve fits with a hydrodynamically motivated halo profile. We systematically investigate the correlation coefficient between the Tully-Fisher residu…
Intrinsic luminosities are related to rotation velocities of disk galaxies by Tully Fisher (TF) relations. The Baryonic TF (BTF) relation has recently been explained with Dark Matter and Newtonian Gravity as well as Modified Newtonian Dynamics (MOND). However, recent work has pointed out that the currently used BTF relation ignores the contribution from hot gas and oversimplifies complex galaxy-scale physics. In this Letter, we advocate the use of the Neutral Hydrogen TF (HITF) relationship, which is free from dust obscuration and stellar evolution effects, as a clean probe of gravity and dyna…
We show that ultra-light scalar dark matter (fuzzy dark matter) in galaxies has a quantum mechanical typical acceleration scale about $10^{-10}\,\mbox{ms}^{-2}$, which leads to the baryonic Tully-Fisher relation. Baryonic matter at central parts of galaxies acts as a boundary condition for dark matter wave equation and influences stellar rotation velocities in halos. Without any modification of gravity or mechanics this model also explains the radial acceleration relation and MOND-like behavior of gravitational acceleration found in galaxies having flat rotation curves. This analysis can be ex…
It has recently been claimed that measurements of the baryonic Tully-Fisher relation (BTFR), a power-law relationship between the observed baryonic masses and outer rotation velocities of galaxies, support the predictions of modified Newtonian dynamics for the slope and scatter in the relation, while challenging the cold dark matter (CDM) paradigm. We investigate these claims, and find that: 1) the scatter in the data used to determine the BTFR is in conflict with observational uncertainties on the data; 2) these data do not make strong distinctions regarding the best-fit BTFR parameters; 3) t…
We present dynamical scaling relations for a homogeneous and representative sample of ~500 massive galaxies, selected only by stellar mass (>10^10 Msun) and redshift (0.025<z<0.05) as part of the ongoing GALEX Arecibo SDSS Survey. We compare baryonic Tully-Fisher (BTF) and Faber-Jackson (BFJ) relations for this sample, and investigate how galaxies scatter around the best fits obtained for pruned subsets of disk-dominated and bulge-dominated systems. The BFJ relation is significantly less scattered than the BTF when the relations are applied to their maximum samples, and is not affected by the …
Dwarf spheroidal satellite galaxies have emerged a powerful probe of small-scale dark matter clustering and of cosmic reionization. They exhibit structural and chemical continuity with dwarf irregular galaxies in the field and with spheroidal galaxies in high-density environments. By combining empirical constraints derived for star formation at low gas column densities and metallicities in the local universe with a model for dark matter and baryonic mass assembly, we provide an analytical description of how the dwarf spheroidals acquired their stellar content. Their progenitors formed stars un…
Thermodynamic Origin of the Tully-Fisher Relation in Dark Matter Dominated Galaxies: A Theoretical-Empirical Derivation
Aristotle University of Thessaloniki（塞萨洛尼基亚里士多德大学）；L.N. Gumilyov Eurasian National University（欧亚国立卢戈尼约夫大学）；Tomsk State University of Control Systems and Radioelectronics（托木斯克州立控制系统与无线电电子大学）
We present 21 cm observations of a 5 x degree region in the Virgo cluster, obtained as part of the Arecibo Galaxy Environment Survey. 13 cluster members are detected, together with 36 objects in the background. We compare and contrast the results from this area with a larger 10 x degree region. We combine the two data sets to produce an HI mass function, which shows a higher detection rate at low masses (but finds fewer massive galaxies) than less sensitive wider-area surveys, such as ALFALFA. We find that the HI-detected galaxies are distributed differently to the non-detections, both spatial…
We examine scaling relations of dispersion-supported galaxies over more than eight orders of magnitude in luminosity by transforming standard fundamental plane parameters into a space of mass (M1/2), radius (r1/2), and luminosity (L1/2). We find that from ultra-faint dwarf spheroidals to giant cluster spheroids, dispersion-supported galaxies scatter about a one-dimensional "fundamental curve" through this MRL space. The weakness of the M1/2-L1/2 slope on the faint end may imply that potential well depth limits galaxy formation in small galaxies, while the stronger dependence on L1/2 on the bri…
Dwarf spheroidal galaxies provide well-known challenges to the standard cold and collisionless dark matter scenario: The too-big-to-fail problem, namely the mismatch between the observed mass enclosed within the half-light radius of dwarf spheroidals and cold dark matter N-body predictions; The hints for inner constant-density cores. While these controversies may be alleviated by baryonic physics and environmental effects, revisiting the standard lore of cold and collisionless dark matter remains an intriguing possibility. Self-interacting dark matter may be the successful proposal to such a s…
Using 22 hydrodynamical simulated galaxies in a LCDM cosmological context we recover not only the observed baryonic Tully-Fisher relation, but also the observed "mass discrepancy--acceleration" relation, which reflects the distribution of the main components of the galaxies throughout their disks. This implies that the simulations, which span the range 52 < V$_{\rm flat}$ < 222 km/s where V$_{\rm flat}$ is the circular velocity at the flat part of the rotation curve, and match galaxy scaling relations, are able to recover the observed relations between the distributions of stars, gas and dark …
Although still under debate, observations generally suggest that dwarf spheroidal (dSph) galaxies exhibit large constant-density cores in the centers, which can hardly be explained by dissipationless cold dark matter simulations without baryonic feedback. Wave dark matter (${ψ{\rm DM}}$), characterized by a single parameter, the dark matter particle mass $m_ψ$, predicts a central soliton core in every galaxy arising from quantum pressure against gravity. Here we apply Jeans analysis assuming a soliton core profile to the kinematic data of eight classical dSphs so as to constrain $m_ψ$, and obt…
The mass discrepancy acceleration relation (MDAR) describes the coupling between baryons and dark matter (DM) in galaxies: the ratio of total-to-baryonic mass at a given radius anti-correlates with the acceleration due to baryons. The MDAR has been seen as a challenge to the $Λ$CDM galaxy formation model, while it can be explained by Modified Newtonian Dynamics. In this Letter we show that the MDAR arises in a $Λ$CDM cosmology once observed galaxy scaling relations are taken into account. We build semi-empirical models based on $Λ$CDM haloes, with and without the inclusion of baryonic effects,…
Tidal dwarf galaxies (TDGs) are recycled objects that form within the collisional debris of interacting/merging galaxies. They are expected to be devoid of non-baryonic dark matter, since they can form only from dissipative material ejected from the discs of the progenitor galaxies. We investigate the gas dynamics in a sample of six bona-fide TDGs around three interacting and post-interacting systems: NGC 4694, NGC 5291, and NGC 7252 ("Atoms for Peace"). For NGC 4694 and NGC 5291 we analyse existing HI data from the Very Large Array (VLA), while for NGC 7252 we present new HI observations from…
This review deals with the inconsistency of inner dark matter density profiles in dwarf galaxies, known as the cusp-core problem. Particularly, we aim to focus on gas-poor dwarf galaxies. One of the most promising solutions to this cold dark matter small scale issue is the stellar feedback but it seems to be only designed for gas-rich dwarfs. However, in the regime of classical dwarfs, this core mechanism becomes negligible. Therefore, it is required to find solutions without invoking these baryonic processes as dark matter cores tend to persist even for these dwarfs, which are rather dark mat…
Motivated by a recently found interesting property of the dark halo surface density within a radius, $r_{\rm max}$, giving the maximum circular velocity, $V_{\rm max}$, we investigate it for dark halos of the Milky Way's and Andromeda's dwarf satellites based on cosmological simulations. We select and analyze the simulated subhalos associated with Milky Way-sized dark halos and find that the values of their surface densities, $Σ_{V_{\rm max}}$, are in good agreement with those for the observed dwarf spheroidal satellites even without employing any fitting procedures. This implies that this sur…
Dark matter (DM) halos of Sc-Im and dwarf spheroidal (dSph) galaxies satisfy scaling laws: halos in lower-luminosity galaxies have smaller core radii, higher central densities, and smaller velocity dispersions. These results are based on maximum-disk rotation curve decompositions for giant galaxies and Jeans equation analysis for dwarfs. (1) We show that spiral, Im, and Sph galaxies with absolute magnitudes M_V > -18 form a sequence of decreasing baryon-to-DM surface density with decreasing luminosity. We suggest that this is a sequence of decreasing baryon retention vs. supernova-driven losse…
Ultralight-axion (ULA) dark matter is one of the possible solutions to resolve small-scale problems, especially the core-cusp problem. This is because ULA dark matter can create a central soliton core in all dark matter haloes stemmed from the quantum pressure against gravity below the de Broglie wavelength, which becomes manifest on astrophysical scales with axion mass range $\sim10^{-22}$ eV. In this work, we apply our non-spherical dynamical models to the kinematic data of eight classical dwarf spheroidals (dSphs) to obtain more reliable and realistic limits on ULA particle mass. This is mo…
The distribution of dark matter (DM) subhalos in our Galaxy remains disputed, leading to varying $γ$-ray and $ν$ flux predictions from their annihilation or decay. In this work, we study how, in the inner Galaxy, subhalo tidal disruption from the Galactic baryonic potential impacts these signals. Based on state-of-the art modeling of this effect from numerical simulations and semi-analytical results, updated subhalo spatial distributions are derived and included in the CLUMPY code. The latter is used to produce a thousand realizations of the $γ$-ray and $ν$ sky. Compared to predictions based o…
We investigate the growth histories of dark matter halos associated with dwarf satellites in Local Group galaxies and the resultant evolution of the baryonic component. Our model is based on the recently proposed property that the mean surface density of a dark halo inside a radius at maximum circular velocity V_max is universal over a large range of V_max. Following that this surface density of 20 Msun/pc^2 well explains dwarf satellites in the Milky Way and Andromeda, we find that the evolution of the dark halo in this common surface-density scale is characterized by the rapid increase of th…
Gamma-ray experiments seeking to detect evidence of dark matter annihilation in dwarf spheroidal galaxies require knowledge of the distribution of dark matter within these systems. We analyze the effects of flattening on the annihilation (J) and decay (D) factors of dwarf spheroidal galaxies with both analytic and numerical methods. Flattening has two consequences: first, there is a geometric effect as the squeezing (or stretching) of the dark matter distribution enhances (or diminishes) the J-factor; second, the line of sight velocity dispersion of stars must hold up the flattened baryonic co…
The relation between properties of galaxies and dark matter halos they reside in can be valuable for structure formation and evolution. This paper focus on the baryonic-to-halo mass ratio (BHMR) and its evolution. We first review unique properties of self-gravitating collisionless dark matter flow (SG-CFD), followed by their application to derive BHMR. To maximize system entropy, the long-range interaction requires a broad size of halos to be formed. These halos facilitate inverse mass and energy cascade from small to large scales with a constant rate of energy cascade $\varepsilon_u$. In addi…
