arXiv subjects

Di Li

Publications and source records attributed to Di Li.

At least 379 records · Page 21Linked to original sources

arXiv2017

OH Survey along Sightlines of Galactic Observations of Terahertz C+

We have obtained OH spectra of four transitions in the $^2Π_{3/2}$ ground state, at 1612, 1665, 1667, and 1720 MHz, toward 51 sightlines that were observed in the Herschel project Galactic Observations of Terahertz C+. The observations cover the longitude range of (32$^\circ$, 64$^\circ$) and (189$^\circ$, 207$^\circ$) in the northern Galactic plane. All of the diffuse OH emissions conform to the so-called 'Sum Rule' of the four brightness temperatures, indicating optically thin emission condition for OH from diffuse clouds in the Galactic plane. The column densities of the HI `halos' N(HI) surrounding molecular clouds increase monotonically with OH column density, N(OH), until saturating when N(HI)=1.0 x 10$^{21}$ cm$^{-2}$ and N (OH) $\geq 4.5\times 10^{15}$ cm$^{-2}$, indicating the presence of molecular gas that cannot be traced by HI. Such a linear correlation, albeit weak, is suggestive of HI halos' contribution to the UV shielding required for molecular formation. About 18% of OH clouds have no associated CO emission (CO-dark) at a sensitivity of 0.07 K but are associated with C$^+$ emission. A weak correlation exists between C$^+$ intensity and OH column density for CO-dark molecular clouds. These results imply that OH seems to be a better tracer of molecular gas than CO in diffuse molecular regions.

astro-ph.GA↗

arXiv2017

Large-Scale Spectroscopic Mapping of the $ρ$ Ophiuchi Molecular Cloud Complex I. The C$_{2}$H to N$_2$H$^+$ Ratio as a Signpost of Cloud Characteristics

We present 2.5-square-degree C$_{2}$H N=1-0 and N$_2$H$^+$ J=1-0 maps of the $ρ$ Ophiuchi molecular cloud complex. These are the first large-scale maps of the $ρ$ Ophiuchi molecular cloud complex with these two tracers. The C$_{2}$H emission is spatially more extended than the N$_2$H$^+$ emission. One faint N$_2$H$^+$ clump Oph-M and one C$_{2}$H ring Oph-RingSW are identified for the first time. The observed C$_{2}$H to N$_{2}$H$^{+}$ abundance ratio ([C$_{2}$H]/[N$_{2}$H$^{+}$]) varies between 5 and 110. We modeled the C$_{2}$H and N$_2$H$^+$ abundances with 1-D chemical models which show a clear decline of [C$_2$H]/[N$_2$H$^+$] with chemical age. Such an evolutionary trend is little affected by temperatures when they are below 40 K. At high density (n$_H$ $>$ 10$^5$ cm$^{-3}$), however, the time it takes for the abundance ratio to drop at least one order of magnitude becomes less than the dynamical time (e.g., turbulence crossing time $\rm \sim$10$^5$ years). The observed [C$_2$H]/[N$_2$H$^+$] difference between L1688 and L1689 can be explained by L1688 having chemically younger gas in relatively less dense regions. The observed [C$_{2}$H]/[N$_{2}$H$^{+}$] values are the results of time evolution, accelerated at higher densities. For the relative low density regions in L1688 where only C$_2$H emission was detected, the gas should be chemically younger.

astro-ph.GA↗

arXiv2016

The Five-hundred-meter Aperture Spherical Radio Telescope (FAST) Project

The Five-hundred-meter Aperture Spherical radio Telescope (FAST) is a Chinese mega-science project funded by the National Development and Reform Commission (NDRC) of the People's Republic of China. The National Astronomical Observatories of China (NAOC) is in charge of its construction and subsequent operation. Upon its expected completion in September 2016, FAST will surpass the 300-meter Arecibo Telescope and the 100-meter Green Bank Telescope in terms of absolute sensitivity in the 70 MHz to 3 GHz bands. In this paper, we report on the project, its current status, the key science goals, and plans for early science.

astro-ph.IM↗

arXiv2016

CH as a Molecular Gas Tracer and C-Shock Tracer Across a Molecular Cloud Boundary in Taurus

We present new observations of all three ground-state transitions of the methylidyne (CH) radical and all four ground-state transitions of the hydroxyl (OH) radical toward a sharp boundary region of the Taurus molecular cloud. These data were analyzed in conjunction with existing CO and dust images. The derived CH abundance is consistent with previous observations of translucent clouds ($0.8\le A_{v} \le 2.1$ mag). The $X({\rm CH})$-factor is nearly a constant at $(1.0\pm0.06)\times 10^{22}$ $\rm {cm^{-2}~K^{-1}~km^{-1}~s}$ in this extinction range, with less dispersion than that of the more widely used molecular tracers CO and OH. CH turns out be a better tracer of total column density in such an intermediate extinction range than CO or OH. Compared with previous observations, CH is overabundant below 1 mag extinction. Such an overabundance of CH is consistent with the presence of a C-shock. CH has two kinematic components, one of which shifts from 5.3 to 6 km s$^{-1}$, while the other stays at 6.8 km s$^{-1}$ when moving from outside toward inside of the cloud. These velocity behaviors exactly match with previous OH observation. The shifting of the two kinematic components indicates colliding streams or gas flow at the boundary region, which could be the cause of the C-shock.

astro-ph.GA↗

arXiv2016

Symmetry and size of membrane protein polyhedral nanoparticles

In recent experiments [T. Basta et al., Proc. Natl. Acad. Sci. U.S.A. 111, 670 (2014)] lipids and membrane proteins were observed to self-assemble into membrane protein polyhedral nanoparticles (MPPNs) with a well-defined polyhedral protein arrangement and characteristic size. We develop a model of MPPN self-assembly in which the preferred symmetry and size of MPPNs emerge from the interplay of protein-induced lipid bilayer deformations, topological defects in protein packing, and thermal effects. With all model parameters determined directly from experiments, our model correctly predicts the observed symmetry and size of MPPNs. Our model suggests how key lipid and protein properties can be modified to produce a range of MPPN symmetries and sizes in experiments.

physics.bio-ph↗

arXiv2016

Intensity Distribution Function and Statistical Properties of Fast Radio Bursts

Fast Radio Bursts (FRBs) are intense radio flashes from the sky that are characterized by millisecond durations and Jansky-level flux densities. We carried out a statistical analysis on FRBs discovered. Their mean dispersion measure, after subtracting the contribution from the interstellar medium of our Galaxy, is found to be $\sim 660\,\rm pc\,cm^{-3}$, supporting their being from cosmological origin. Their energy released in radio band spans about two orders of magnitude, with a mean value of $\sim 10^{39}$ ergs. More interestingly, although the FRB study is still in a very early phase, the published collection of FRBs enables us to derive a useful intensity distribution function. For the 16 non-repeating FRBs detected by Parkes telescope and the Green Bank Telescope, the intensity distribution can be described as $dN/dF_{\rm obs} = (4.1 \pm 1.3) \times 10^3 \, F_{\rm obs}^{-1.1\pm0.2} \; \rm sky^{-1}\,day^{-1}$, where $F_{\rm obs}$ is the observed radio fluence in units of Jy~ms. Here the power-law index is significantly flatter than the expected value of 2.5 for standard candles distributed homogeneously in a flat Euclidean space. Based on this intensity distribution function, the Five-hundred-meter Aperture Spherical radio Telescope (FAST) will be able to detect about 5 FRBs for every 1000 hours of observation time.

astro-ph.HE↗

arXiv2016

Star formation laws in both Galactic massive clumps and external galaxies: An extensive study with dust continuum, HCN (4-3), and CS (7-6)

We observed 146 Galactic clumps in HCN (4-3) and CS (7-6) with the Atacama Submillimeter Telescope Experiment (ASTE) 10-m telescope. A tight linear relationship between star formation rate and gas mass traced by dust continuum emission was found for both Galactic clumps and the high redshift (z>1) star forming galaxies (SFGs), indicating a constant gas depletion time of ~100 Myr for molecular gas in both Galactic clumps and high z SFGs. However, low z galaxies do not follow this relation and seem to have a longer global gas depletion time. The correlations between total infrared luminosities (L_TIR) and molecular line luminosities (L'_mol) of HCN (4-3) and CS (7-6) are tight and sublinear extending down to clumps with LTIR~10^{3} L_sun. These correlations become linear when extended to external galaxies. A bimodal behavior in the LTIR--L'mol correlations was found for clumps with different dust temperature, luminosity-to-mass ratio, and sigmaline/sigmavir. Such bimodal behavior may be due to evolutionary effects. The slopes of LTIR--L'mol correlations become more shallow as clumps evolve. We compared our results with lower J transition lines in wu et al. (2010). The correlations between clump masses and line luminosities are close to linear for low effective excitation density tracers but become sublinear for high effective excitation density tracers for clumps with LTIR larger than LTIR~10^4.5 Lsun. High effective excitation density tracers cannot linearly trace the total clump masses, leading to a sublinear correlations for both Mclump-L'mol and LTIR-L'mol relations.

astro-ph.GA↗

arXiv2016

Cloud Structure of Galactic OB Cluster Forming Regions from Combining Ground and Space Based Bolometric Observations

We have developed an iterative procedure to systematically combine the millimeter and submillimeter images of OB cluster-forming molecular clouds, which were taken by ground based (CSO, JCMT, APEX, IRAM-30m) and space telescopes (Herschel, Planck). For the seven luminous ($L$$>$10$^{6}$ $L_{\odot}$) Galactic OB cluster-forming molecular clouds selected for our analyses, namely W49A, W43-Main, W43-South, W33, G10.6-0.4, G10.2-0.3, G10.3-0.1, we have performed single-component, modified black-body fits to each pixel of the combined (sub)millimeter images, and the Herschel PACS and SPIRE images at shorter wavelengths. The $\sim$10$"$ resolution dust column density and temperature maps of these sources revealed dramatically different morphologies, indicating very different modes of OB cluster-formation, or parent molecular cloud structures in different evolutionary stages. The molecular clouds W49A, W33, and G10.6-0.4 show centrally concentrated massive molecular clumps that are connected with approximately radially orientated molecular gas filaments. The W43-Main and W43-South molecular cloud complexes, which are located at the intersection of the Galactic near 3-kpc (or Scutum) arm and the Galactic bar, show a widely scattered distribution of dense molecular clumps/cores over the observed $\sim$10 pc spatial scale. The relatively evolved sources G10.2-0.3 and G10.3-0.1 appear to be affected by stellar feedback, and show a complicated cloud morphology embedded with abundant dense molecular clumps/cores. We find that with the high angular resolution we achieved, our visual classification of cloud morphology can be linked to the systematically derived statistical quantities (i.e., the enclosed mass profile, the column density probability distribution function, the two-point correlation function of column density, and the probability distribution function of clump/core separations).

astro-ph.GA↗

arXiv2016

Physical properties of CO-dark molecular gas traced by C$^+$

Neither HI nor CO emission can reveal a significant quantity of so-called dark gas in the interstellar medium (ISM). It is considered that CO-dark molecular gas (DMG), the molecular gas with no or weak CO emission, dominates dark gas. We identified 36 DMG clouds with C$^+$ emission (data from Galactic Observations of Terahertz C+ (GOT C+) project) and HINSA features. Based on uncertainty analysis, optical depth of HI $τ\rm_{HI}$ of 1 is a reasonable value for most clouds. With the assumption of $τ\rm_{HI}=1$, these clouds were characterized by excitation temperatures in a range of 20 K to 92 K with a median value of 55 K and volume densities in the range of $6.2\times10^1$ cm$^{-3}$ to $1.2\times 10^3$ cm$^{-3}$ with a median value of $2.3\times 10^2$ cm$^{-3}$. The fraction of DMG column density in the cloud ($f\rm_{DMG}$) decreases with increasing excitation temperature following an empirical relation $f\rm_{DMG}=-2.1\times 10^{-3}T_(ex,τ_{HI}=1)$+1.0. The relation between $f\rm_{DMG}$ and total hydrogen column density $N_H$ is given by $f\rm_{DMG}$=$1.0-3.7\times 10^{20}/N_H$. The values of $f\rm_{DMG}$ in the clouds of low extinction group ($A\rm_V \le 2.7$ mag) are consistent with the results of the time-dependent, chemical evolutionary model at the age of ~ 10 Myr. Our empirical relation cannot be explained by the chemical evolutionary model for clouds in the high extinction group ($A\rm_V > 2.7$ mag). Compared to clouds in the low extinction group ($A\rm_V \le 2.7$ mag), clouds in the high extinction group ($A\rm_V > 2.7$ mag) have comparable volume densities but excitation temperatures that are 1.5 times lower. Moreover, CO abundances in clouds of the high extinction group ($A\rm_V > 2.7$ mag) are $6.6\times 10^2$ times smaller than the canonical value in the Milky Way. #[Full version of abstract is shown in the text.]#

astro-ph.GA↗

arXiv2016

Massive Quiescent Cores in Orion: VI. The Internal Structures and a Candidate of Transiting Core in NGC 2024 Filament

We present a multi-wavelength observational study of the NGC 2024 filament using infrared to sub-millimeter continuum and the NH$_3$ $(1,1)$ and $(2,2)$ inversion transitions centered on FIR-3, the most massive core therein. FIR-3 is found to have no significant infrared point sources in the Spitzer/IRAC bands. But the NH$_3$ kinetic temperature map shows a peak value at the core center with $T_{\rm k}=25$ K which is significantly higher than the surrounding level ($T_{\rm k}=15-19$ K). Such internal heating signature without an infrared source suggests an ongoing core collapse possibly at a transition stage from first hydrostatic core (FHSC) to protostar. The eight dense cores in the filament have dust temperatures between 17.5 and 22 K. They are much cooler than the hot ridge ($T_{\rm d}=55$ K) around the central heating star IRS-2b. Comparison with a dust heating model suggests that the filament should have a distance of $3-5$ pc from IRS-2b. This value is much larger than the spatial extent of the hot ridge, suggesting that the filament is spatially separated from the hot region along the line of sight.

astro-ph.GA↗

arXiv2016

Discovery of an extremely wide-angle bipolar outflow in AFGL 5142

Most bipolar outflows are associated with individual young stellar objects and have small opening angles. Here we report the discovery of an extremely wide-angle ($\sim$180$\arcdeg$) bipolar outflow ("EWBO") in a cluster forming region AFGL 5142 from low-velocity emission of the HCN (3-2) and HCO$^{+}$ (3-2) lines. This bipolar outflow is along a north-west to south-east direction with a line-of-sight flow velocity of about 3 km~s$^{-1}$ and is spatially connected to the high-velocity jet-like outflows. It seems to be a collection of low-velocity material entrained by the high-velocity outflows due to momentum feedback. The total ejected mass and mass loss rate due to both high velocity jet-like outflows and the "EWBO" are $\sim$24.5 M$_{\sun}$ and $\sim1.7\times10^{-3}$ M$_{\sun}$~yr$^{-1}$, respectively. Global collapse of the clump is revealed by the "blue profile" in the HCO$^{+}$ (1-0) line. A hierarchical network of filaments was identified in NH$_{3}$ (1,1) emission. Clear velocity gradients of the order of 10 km~s$^{-1}$~pc$^{-1}$ are found along filaments, indicating gas inflow along the filaments. The sum of the accretion rate along filaments and mass infall rate along the line of sight is $\sim$3.1$\times10^{-3}$ M$_{\sun}$~yr$^{-1}$, which exceeds the total mass loss rate, indicating that the central cluster is probably still gaining mass. The central cluster is highly fragmented and 22 condensations are identified in 1.1 mm continuum emission. The fragmentation process seems to be determined by thermal pressure and turbulence. The magnetic field may not play an important role in fragmentation.

astro-ph.GA↗

arXiv2016

Discovery of Two New Pulsars in 47 Tucanae (NGC 104)

We report the discovery of two new millisecond pulsars (PSRs J0024$-$7204aa and J0024$-$7204ab) in the globular cluster 47\,Tucanae (NGC 104). Our results bring the total number of pulsars in 47\,Tucanae to 25. These pulsars were discovered by reprocessing archival observations from the Parkes radio telescope. We reprocessed the data using a standard search procedure based on the PRESTO software package as well as using a new method in which we incoherently added the power spectra corresponding to $\sim$1100\,hr of observations. The newly discovered PSR~J0024$-$7204aa, has a pulse frequency of $\rm \sim$541\,Hz (corresponding to a $\rm \sim$1.84 ms period), which is higher than any other pulsars currently known in the cluster and ranks 12$^{\rm{th}}$ amongst all the currently known pulsars. The dispersion measure of this pulsar, 24.941(7)\,cm$^{-3}$ pc, is the highest in the cluster. The second discovered pulsar, PSR~J0024$-$7204ab, is an isolated pulsar with a pulse frequency of $\rm \sim$270\,Hz (corresponding to a period of $\rm \sim$3.70 ms).

astro-ph.HE↗

arXiv2016

Gas Kinematics and Star Formation in the Filamentary IRDC G34.43+0.24

We performed a multiwavelength study toward infrared dark cloud (IRDC) G34.43+0.24. New maps of 13CO $J$=1-0 and C18}O J=1-0 were obtained from the Purple Mountain Observatory (PMO) 13.7 m radio telescope. At 8 um (Spitzer - IRAC), IRDC G34.43+0.24 appears to be a dark filament extended by 18 arcmin along the north-south direction. Based on the association with the 870 um and C18O J=1-0 emission, we suggest that IRDC G34.43+0.24 should not be 18 arcmin in length, but extend by 34 arcmin. IRDC G34.43+0.24 contains some massive protostars, UC H II regions, and infrared bubbles. The spatial extend of IRDC G34.43+0.24 is about 37 pc assuming a distance of 3.7 kpc. IRDC G34.43+0.24 has a linear mass density of 1.6*10^{3} M_{sun} pc^{-1}, which is roughly consistent with its critical mass to length ratio. The turbulent motion may help stabilizing the filament against the radial collapse. Both infrared bubbles N61 and N62 show a ringlike structure at 8 um. Particularly, N61 has a double-shell structure, which has expanded into IRDC G34.43+0.24. The outer shell is traced by 8 um and 13}CO J=1-0 emission, while the inner shell is traced by 24 um and 20 cm emission. We suggest that the outer shell (9.9*10^{5} yr) is created by the expansion of H II region G34.172+0.175, while the inner shell (4.1-6.3*10^{5} yr) may be produced by the energetic stellar wind of its central massive star. From GLIMPSE I catalog, we selected some Class I sources with an age of 10^{5} yr. These Class I sources are clustered along the filamentary molecular cloud.

astro-ph.SR↗

arXiv2016

Evolution of OH and CO-dark Molecular Gas Fraction Across a Molecular Cloud Boundary In Taurus

We present observations of 12CO J=1-0, 13CO J=1-0, HI, and all four ground-state transitions of the hydroxyl (OH) radical toward a sharp boundary region of the Taurus molecular cloud. Based on a PDR model that reproduces CO and [CI] emission from the same region, we modeled the three OH transitions, 1612, 1665, 1667 MHz successfully through escape probability non-LTE radiative transfer model calculations. We could not reproduce the 1720 MHz observations, due to un-modeled pumping mechanisms, of which the most likely candidate is a C-shock. The abundance of OH and CO-dark molecular gas (DMG) are well constrained. The OH abundance [OH]/[H2] decreases from 8*10-7 to 1*10-7 as Av increases from 0.4 to 2.7 mag, following an empirical law [OH]/[H2]= 1.5 * 10^{-7} + 9.0 * 10^{-7} * exp(-Av/0.81), which is higher than PDR model predictions for low extinction regions by a factor of 80. The overabundance of OH at extinctions at or below 1 mag is likely the result of a C-shock. The dark gas fraction (DGF, defined as fraction of molecular gas without detectable CO emission) decreases from 80% to 20%, following a gaussian profile DGF= 0.90 * exp(-( Av -0.79 )/0.71)^2) This trend of the DGF is consistent with our understanding that the DGF drops at low visual extinction due to photodissociation of H2 and drops at high visual extinction due to CO formation. The DGF peaks in the extinction range where H2 has already formed and achieved self-shielding but 12CO has not. Two narrow velocity components with a peak-to-peak spacing of ~ 1 km s-1 were clearly identified. Their relative intensity and variation in space and frequency suggest colliding streams or gas flows at the boundary region.

astro-ph.GA↗

arXiv2015

Planck cold clumps in the $λ$ Orionis complex: I. Discovery of an extremely young Class 0 protostellar object and a proto-brown dwarf candidate in a bright rimmed clump PGCC G192.32-11.88

We are performing a series of observations with ground-based telescopes toward Planck Galactic cold clumps (PGCCs) in the $λ$ Orionis complex in order to systematically investigate the effects of stellar feedback. In the particular case of PGCC G192.32-11.88, we discovered an extremely young Class 0 protostellar object (G192N) and a proto-brown dwarf candidate (G192S). G192N and G192S are located in a gravitationally bound bright-rimmed clump. The velocity and temperature gradients seen in line emission of CO isotopologues indicate that PGCC G192.32-11.88 is externally heated and compressed. G192N probably has the lowest bolometric luminosity ($\sim0.8$ L$_{\sun}$) and accretion rate (6.3$\times10^{-7}$ M$_{\sun}$~yr$^{-1}$) when compared with other young Class 0 sources (e.g. PACS Bright Red sources (PBRs)) in the Orion complex. It has slightly larger internal luminosity ($0.21\pm0.01$ L$_{\sun}$) and outflow velocity ($\sim$14 km~s$^{-1}$) than the predictions of first hydrostatic cores (FHSCs). G192N might be among the youngest Class 0 sources, which are slightly more evolved than a FHSC. Considering its low internal luminosity ($0.08\pm0.01$ L$_{\odot}$) and accretion rate (2.8$\times10^{-8}$ M$_{\sun}$~yr$^{-1}$), G192S is an ideal proto-brown dwarf candidate. The star formation efficiency ($\sim$0.3\%-0.4\%) and core formation efficiency ($\sim$1\%) in PGCC G192.32-11.88 are significantly smaller than in other giant molecular clouds or filaments, indicating that the star formation therein is greatly suppressed due to stellar feedback.

astro-ph.GA↗

arXiv2015

Distributed Bayesian Quickest Change Detection in Sensor Networks via Two-layer Large Deviation Analysis

We propose a distributed Bayesian quickest change detection algorithm for sensor networks, based on a random gossip inter-sensor communication structure. Without a control or fusion center, each sensor executes its local change detection procedure in a parallel and distributed fashion, interacting with its neighbor sensors via random inter-sensor communications to propagate information. By modeling the information propagation dynamics in the network as a Markov process, two-layer large deviation analysis is presented to analyze the performance of the proposed algorithm. The first-layer analysis shows that the relation between the probability of false alarm and the conditional averaged detection delay satisfies the large deviation principle, implying that the probability of false alarm according to a rare event decays to zero at an exponentially fast rate when the conditional averaged detection decay increases, where the Kullback-Leibler information number is established as a crucial factor. The second-layer analysis shows that the probability of the rare event that not all observations are available at a sensor decays to zero at an exponentially fast rate when the averaged number of communications increases, where the large deviation upper and lower bounds for this rate are also derived, based on which we show that the performance of the distributed algorithm converges exponentially fast to that of the centralized one, by proving that the defined distributed Kullback-Leibler information number converges to the centralized Kullback-Leibler information number.

cs.IT↗

arXiv2015

Learning-Based Distributed Detection-Estimation in Sensor Networks with Unknown Sensor Defects

We consider the problem of distributed estimation of an unknown deterministic scalar parameter (the target signal) in a wireless sensor network (WSN), where each sensor receives a single snapshot of the field. We assume that the observation at each node randomly falls into one of two modes: a valid or an invalid observation mode. Specifically, mode one corresponds to the desired signal plus noise observation mode (\emph{valid}), and mode two corresponds to the pure noise mode (\emph{invalid}) due to node defect or damage. With no prior information on such local sensing modes, we introduce a learning-based distributed procedure, called the mixed detection-estimation (MDE) algorithm, based on iterative closed-loop interactions between mode learning (detection) and target estimation. The online learning step re-assesses the validity of the local observations at each iteration, thus refining the ongoing estimation update process. The convergence of the MDE algorithm is established analytically. Asymptotic analysis shows that, in the high signal-to-noise ratio (SNR) regime, the MDE estimation error converges to that of an ideal (centralized) estimator with perfect information about the node sensing modes. This is in contrast to the estimation performance of a naive average consensus based distributed estimator (without mode learning), whose estimation error blows up with an increasing SNR.

cs.IT↗

arXiv2015

Outflows and Bubbles in Taurus: Star-formation Feedback Sufficient to Maintain Turbulence

We have identified outflows and bubbles in the Taurus molecular cloud based on the $\sim 100$ deg$^2$ Five College Radio Astronomy Observatory $^{12}$CO(1-0) and $^{13}$CO(1-0) maps and the Spitzer young stellar object catalogs. In the main 44 deg$^2$ area of Taurus we found 55 outflows, of which 31 were previously unknown. We also found 37 bubbles in the entire 100 deg$^2$ area of Taurus, all of which had not been found before. The total kinetic energy of the identified outflows is estimated to be $\bf \sim 3.9 \times 10^{45}$ erg, which is \textbf{1\%} of the cloud turbulent energy. The total kinetic energy of the detected bubbles is estimated to be $\sim 9.2 \times 10^{46}$ erg, which is 29\% of the turbulent energy of Taurus. The energy injection rate from outflows is $\bf \sim 1.3 \times 10^{33}~\rm erg\ s^{-1}$, \textbf{0.4 - 2 times} the dissipation rate of the cloud turbulence. The energy injection rate from bubbles is $\sim 6.4 \times 10^{33}$ erg s$^{-1}$, \textbf{2 - 10 times} the turbulent dissipation rate of the cloud. The gravitational binding energy of the cloud is $\bf \sim 1.5 \times 10^{48}$ {\bf erg}, \textbf{385} and 16 times the energy of outflows and bubbles, respectively. We conclude that neither outflows nor bubbles can \textbf{provide enough energy to balance the overall gravitational binding energy and the turbulent energy of Taurus. However,} in the current epoch, stellar feedback is sufficient to maintain the observed turbulence in Taurus.

astro-ph.GA↗