We consider the kinematic distances to nearby galaxies obtained by the Numerical Action Method (NAM) based on the Cosmic-flow-3 survey data. NAM-distances are compared with 418 high-precision distances measured by the Tip of the Red Giant Branch (TRGB) method using the Hubble Space Telescope. We estimated the average difference = -0.30 ± 0.08 Mpc and the standard deviation of 1.57 Mpc. Approximately the same difference in the distance scale is obtained in comparison with less accurate distance estimates through the membership of galaxies in known groups or from the Tully-Fisher relation. We conclude that the NAM method provides distance estimates with an accuracy of 20
We describe the results of observations with the 100 m Robert C. Byrd Green Bank Telescope in the H i line of 105 nearby dwarf galaxies, 60 of which were discovered recently in the DESI Legacy Imaging Surveys. Of 105 objects observed, we detected 77 galaxies with the following median parameters: an H i flux of 0.69 Jy km s ^−1 , a heliocentric velocity of 732 km s ^−1 , and a W _50 line width of 32 km s ^−1 . Seventy are isolated late-type objects and 35 are new probable satellites of nearby spiral galaxies (NGC 628, NGC 2787, NGC 3556, NGC 4490, NGC 4594, and NGC 5055). The detected galaxies are predominantly gas-rich systems with a median gas-to-stellar-mass ratio of 1.87. In general, they follow the classic Tully–Fisher relation obtained for large disk-dominated spiral galaxies if their M _21 magnitudes are used instead of B magnitudes.
The 6-meter BTA telescope has been used to determine radial velocities for 40 galaxies, recently identified in the DESI Legacy Imaging Surveys as nearby objects. Half of them have kinematic distances within 11 Mpc being new probable companions to the bright Local Volume galaxies: NGC628, Maffei2, NGC2787, M81, NGC4605 and NGC4631. Six relatively isolated objects with heliocentric velocities in the range of [-150, +70]km s^-1, together with the blue compact dwarf NGC 6789, form a diffuse association of dwarf galaxies located in the near part of the Local Void.
We have undertaken a search for satellites around edge-on galaxies in the EGIPS catalog, which contains 16551 objects with declinations above -30 deg. We searched for systems with a central galaxy dominating in brightness by at least 1 mag compared to its companions. As a result, we discovered 1097 candidate satellites around 764 EGIPS galaxies with projected distances less than 500 kpc and a radial velocity difference less than 300 km/s. Of these, 757 satellites around 547 central galaxies have radial velocity accuracies higher than 20 km/s and satisfy the gravitationally bound condition. The ensemble of satellites is characterized by an average projected distance of 84 kpc and an average radial velocity dispersion of 103 km/s. Treating small satellites as test particles moving on isotropic orbits around central EGIPS galaxies, we determined the projected (orbital) masses of the edge-on galaxies. Within the luminosity range of 1.3*10^10 to 42*10^{10} Lsun, the total mass of the systems is well described by a linear dependence log(Mp)~0.88*log(g) with an average total mass-to-$K$-band luminosity equal to 17.5+-0.8 Msun/Lsun, which is typical for nearby spiral galaxies such as the Milky Way, M 31 and M 81.
The tip of the red giant branch (TRGB) allows for the measurement of precise and accurate distances to nearby galaxies, based on the brightest ascent of low-mass red giant branch stars before they undergo the helium flash. With the advent of JWST, there is great promise to utilize the technique to measure galaxy distances out to at least 50 Mpc, significantly further than HST's reach of 20 Mpc. However, with any standard candle, it is first necessary to provide an absolute reference. Here we use Cycle 1 data to provide an absolute calibration in the F090W filter. F090W is most similar to the F814W filter commonly used for TRGB measurements with HST, which had been adopted by the community due to minimal dependence from the underlying metallicities and ages of stars. The imaging we use was taken in the outskirts of NGC 4258, which has a direct geometrical distance measurement from the Keplerian motion of its water megamaser. Utilizing several measurement techniques, we find $M_{TRGB}^{F090W}$ = -4.362 $\pm$ 0.033 (stat) $\pm$ 0.045 (sys) mag (Vega) for the metal-poor TRGB. We also perform measurements of the TRGB in two Type Ia supernova hosts, NGC 1559, and NGC 5584. We find good agreement between our TRGB distances and previous distance determinations to these galaxies from Cepheids ($\Delta$ = 0.01 $\pm$ 0.06 mag), with these differences being too small to explain the Hubble tension ($\sim$0.17 mag). As a final bonus, we showcase the serendipitous discovery of a faint dwarf galaxy near NGC 5584.
We analyzed images of every northern hemisphere Sd galaxy listed in the Third Reference Catalogue of Bright Galaxies with a relatively face-on inclination (theta <= 30 degrees). Specifically, we measured the spiral arms' winding angle, phi, in 85 galaxies. We applied a novel black hole mass planar scaling relation involving the rotational velocities (from the literature) and pitch angles of each galaxy to predict central black hole masses. This yielded 23 galaxies, each having at least a 50% chance of hosting a central intermediate-mass black hole (IMBH), 10(2) < M-center dot <= 10(5)M(circle dot). These 23 nearby (less than or similar to 50 Mpc) targets may be suitable for an array of follow-up observations to check for active nuclei. Based on our full sample of 85 Sd galaxies, we estimate that the typical Sd galaxy (which tends to be bulgeless) harbors a black hole with log (M-center dot/M-circle dot) = 6.00 +/- 0.14 , but with a 27.7% chance of hosting an IMBH, making this morphological type of galaxy fertile ground for hunting elusive IMBHs. Thus, we find that a similar to 10(6) M-circle dot black hole corresponds roughly to the onset of bulge development and serves as a conspicuous waypoint along the galaxy-supermassive black hole coevolution journey. Our survey suggests that >1.22% of bright galaxies (B-T less than or similar to 15.5 mag) in the local Universe host an IMBH (i.e., the "occupation fraction"), which implies a number density >4.96 x 10(-6) Mpc(-3) for central IMBHs. Finally, we observe that Sd galaxies exhibit an unexpected diversity of properties that resemble the general population of spiral galaxies, albeit with an enhanced signature of the eponymous prototypical traits (i.e., low masses, loosely wound spiral arms, and smaller rotational velocities).
The interacting binary system NGC 4490/85 = Arp 269 is intermediate in mass between the Milky Way/Large Magellanic Cloud and the Large/Small Magellanic Cloud binary systems. It is a system of 14 known galaxies. We estimate the total Newtonian gravitating mass of the NGC\,4490/85 group to be M_T = (1.37 +- 0.43) times 10^{12} M_Sun using radial velocities and projected separations of its 13~candidate members. The system of dwarf satellites in the group demonstrates signs of coherent rotation in the same direction as that of the extended HI-shell surrounding the central interacting galaxy pair. The origin of this phase-space correlated population of star-forming late-type satellite galaxies raises questions in view of the planes-of-satellites observed around more massive galaxy pairs that are, however, made up of old early-type dwarf galaxies. We also report the detection of a candidate stellar Plume near the binary. This elongated structure of low surface brightness is a likely optical counterpart to the HI-tail north of NGC 4490/85, recently discovered by the FAST radio telescope.
We report the discovery of 20 new dwarf galaxies in the Local Volume identified as optical counterparts to the Five-hundred-meter Aperture Spherical radio Telescope (FAST) All Sky HI Survey (FASHI) sources. The galaxies have a median stellar mass of 7.8 × 106 M⊙ and a median HI mass of 1.0 × 107 M⊙. Most of them are field galaxies, while three are probable members of the M 101 and M 106 groups. We also found seven FASHI radio sources to be probable dark HI clouds in nearby groups. Together with four other known HI clouds in the local groups, their mean-square radial velocity difference of 49 km s−1 with respect to the host galaxies yields an average total mass of (2.7 ± 1.0)×1011 M⊙ for these groups on the projected scale of 90 kpc.
We undertook a search for new nearby dwarf galaxies outside the known groups in the Local Volume using the data on DESI Legacy Imaging Surveys. In a wide sky area of ~5000 square degrees directed toward the Local Void, we found only 12 candidates to nearby low mass galaxies. Almost all of them are classified as irregular or transition type dwarfs. Additionally, we examined areas of the sky exposed with the Hyper Suprime Camera of the Subaru telescope (~700 square degrees) and found nine more candidates to nearby dwarfs. Finally, nine candidates to the Local Volume were selected by us from the Zaritsky's SMUDG catalog that contains 7070 ultra-diffuse objects automatically detected in the whole area of the DESI surveys. We estimated a fraction of quiescent dSph galaxies in the general cosmic field to be less than 10 percent. Используя данные обзора DESI Legacy Imaging Surveys, мы предприняли поиск новых близких карликовых галактик вне известных групп в Местном Объеме. В обширной области неба площадью примерно 5000 квадратных градусов, направленной к Местному Войду, мы нашли только 12 кандидатов в близкие галактики низкой массы. Все они классифицированы как иррегу лярные либо карлики переходного типа. Дополнительно мы обследовали площади неба, снятые телескопом Субару с камерой Hyper Suprime Camera (около 700 кв. град.) и обнаружили еще девять кандидатов в близкие карлики. Наконец, 9 кандидатов в Местный Объем были отобраны нами из каталога Зарицкого (SMUDG), который содержит 7070 ультра-диффузных объектов, найденных автоматически на всей площади обзора DESI. Мы оцениваем долю "спокойных" dSph галактик в общем космическом поле не более 10 процентов.
We report on the discovery of three large diffuse dwarf (LDD) galaxies located in isolated triple systems. They have effective diameters of 3.6 ÷10.0 kpc and effective surface brightness of 26.2 ÷ 27.3 m/sq. arcsec. We note that the LDD galaxies tend to occur in small groups with a very low dispersion of radial velocities. The total (orbital) mass of the triplets approximately equals to their integral stellar mass within velocity measurement errors. The presence of LDD galaxies in cold multiple systems seems mysterious.
Based on the fluxes of 1400 nearby galaxies observed in far ultraviolet (FUV) and in the H α line, we determined the global star formation rate per unit Universe volume, j_SFR=(1.34± 0.16)× 10^-2M_⊙ yr ^-1 Mpc ^-3 . With the current star formation rate ( SFR ), ( 65± 4)% of the observed stellar mass is reproduced in the cosmological time of 13.8 billion years. The neutral gas reserves in the Local Volume with a radius of 11 Mpc will facilitate the current SFR on a scale of approximately another 5 billion years.
Using long-term INTEGRAL hard X-ray observations, we have put upper limits on the bolometric luminosity ( $$L_{\textrm{bol}}\lesssim 10^{41}$$ erg s $${}^{-1}$$ ) of the nuclei of 72 nearby dwarf galaxies located in the M81 field. This has allowed us to constrain the fraction of galaxies in which the central black hole accretes matter at a rate above 0.1 $${\%}$$ of the critical one. Under simple assumptions about the distributions of black hole masses and accretion rates this fraction does not exceed 9 $${\%}$$ . Reliable estimates of the central black hole masses are required to obtain more stringent constraints on the fraction of AGNs.
Images of 10 galaxies in F814W and F606W filters obtained on the Hubble Space Telescope (HST) are used to construct color-magnitude diagrams for the star population of these galaxies. The distances to the galaxies are estimated from the luminosity of the tip of the red giant branch. The galaxies examined here have radial velocities from 250 to 760 km/s relative to the centroid of the Local Group and distances ranging from 3.7 to 13.0 Mpc. Several other observed galaxies with low radial velocities are noted at distances beyond the limit of 13 Mpc.
ABSTRACT The dwarf irregular galaxy HIPASS J1131-31 was discovered as a source of HI emission at low redshift in such close proximity of a bright star that we call it Peekaboo. The galaxy resolves into stars in images with Hubble Space Telescope, leading to a distance estimate of 6.8 ± 0.7 Mpc. Spectral optical observations with the Southern African Large Telescope reveal HIPASS J1131-31 to be one of the most extremely metal-poor galaxies known with the gas-phase oxygen abundance 12 + log(O/H) = 6.99 ± 0.16 dex via the direct [O iii] 4363 line method and 6.87 ± 0.07 dex from the two strong line empirical methods. The red giant branch of the system is tenuous compared with the prominence of the features of young populations in the colour-magnitude diagram, inviting speculation that star formation in the galaxy only began in the last few Gyr.
We performed a search for faint low-surface-brightness dwarf galaxies around the major spiral galaxy M 101 and in the large rectangular area within SGL = [30–80]° and SGB = [10–37]° spanning a chain of galaxies: M 63, M 51, M 101, and NGC 6503. We based our search on data from DESI Legacy Imaging Surveys. We discovered six new probable dwarf members of the complex. We present a list of 25 prospective members of the M 101 group and estimate the total mass and the total-mass-to-K-band-luminosity ratio of the group as (1.02 ± 0.42)×1012 M⊙ and (16.0 ± 6.5) M⊙/L⊙, respectively. We note that the average dark mass-to-luminosity ratio in the groups around M 63, M 51, and M 101 is (12 ± 4) M⊙/L⊙, which is almost an order of magnitude lower than the global cosmic ratio, (102 ± 5) M⊙/L⊙.
We estimated the angular momentum, $J$, of $720$ galaxies in the Local Volume with distances $r < 12$ Mpc. The distribution of the average angular momentum along the Hubble sequence has a maximum at the morphological type $T= 4$ (Sbc), while the dispersion of the $J$-values for galaxies is minimal. Among the Local Volume population, 27 elite spiral galaxies stand out, with an angular momentum greater than 0.15 of the Milky Way, $J > 0.15 J_{MW}$, making the main contribution ($ > 90\%$) to the total angular momentum of galaxies in the considered volume. Using observational data on the kinematics and structure of these galaxies, we determined the direction of their spins. We present the first map of the distribution of the spins of 27 nearby massive spiral galaxies in the sky and note that their pattern does not exhibit significant alignment with respect to the Local Sheet plane. The relationship between the magnitude of the angular momentum and stellar mass of the local galaxies is well represented by a power law with an exponent of ($5/3$) over an interval of $6$ orders of magnitude of the mass of galaxies.
We undertook a search for new dwarf galaxies in the vicinity of relatively isolated nearby galaxies with distances $D < 12$ Mpc and stellar masses in the $2\times10^{11}-3\times10^8~M_{\odot}$ interval, using the data from the DESI Legacy Imaging Surveys. Around the 46 considered Local Volume galaxies, $67$ new candidates for satellites of these galaxies were found. About half of them are classified as spheroidal dwarfs of low surface brightness. The new galaxies are included in the Local Volume database (LVGDB), which now contains 1421 objects, being 63% more than the Updated Nearby Galaxy Catalog.
Results of surface photometry of 50 galaxies in the Local Volume based on archived images obtained with the Hubble Space Telescope are presented. Integrated magnitudes in the V and I bands are introduced for the chosen galaxies, along with brightness and color profiles. The obtained photometric parameters are compared with the measurements of other authors.
Представлены результаты поверхностной фотометрии 50-ти галактик в Местном объеме на основе архивных изображений, полученных на космическом телескопе Хаббла. Для выборки галактик приводятся интегральные величины в полосах V и I, а также профили яркости и цвета. Проведено сравнение полученных фотометрических параметров с измерениями других авторов. The results of surface photometry of 50 galaxies in the Local Volume based on archival images obtained with the Hubble Space Telescope are presented. For the sample of galaxies, the integrated magnitudes in the V and I bands are given, as well as the brightness and color profiles. The obtained photometric parameters are compared with the measurements of other authors.
The WALLABY pilot survey has been conducted using the Australian SKA Pathfinder (ASKAP). The integrated 21-cm HI line spectra are formed in a very different manner compared to usual single-dish spectra Tully-Fisher measurements. It is thus extremely important to ensure that slight differences (e.g. biases due to missing flux) are quantified and understood in order to maximise the use of the large amount of data becoming available soon. This article is based on four fields for which the data are scientifically interesting by themselves. The pilot data discussed here consist of 614 galaxy spectra at a rest wavelength of 21cm. Of these spectra, 472 are of high enough quality to be used to potentially derive distances using the Tully-Fisher relation. We further restrict the sample to the 251 galaxies whose inclination is sufficiently close to edge-on. For these, we derive Tully-Fisher distances using the deprojected WALLABY velocity widths combined with infrared (WISE W1) magnitudes. The resulting Tully-Fisher distances for the Eridanus, Hydra, Norma and NGC 4636 clusters are 21.5, 53.5, 69.4 and 23.0 Mpc respectively, with uncertainties of 5–10%, which are better or equivalent to the ones obtained in studies using data obtained with giant single dish telescopes. The pilot survey data show the benefits of WALLABY over previous giant single-dish telescope surveys. WALLABY is expected to detect around half a million galaxies with a mean redshift of z = 0.05 (200 Mpc). This study suggests that about 200,000 Tully-Fisher distances might result from the survey.