Formation Law Research Articles

CARMA SURVEY TOWARD INFRARED-BRIGHT NEARBY GALAXIES (STING). II. MOLECULAR GAS STAR FORMATION LAW AND DEPLETION TIME ACROSS THE BLUE SEQUENCE

We present an analysis of the relationship between molecular gas and current star formation rate surface density at sub-kpc and kpc scales in a sample of 14 nearby star-forming galaxies. Measuring the relationship in the bright, high molecular gas surface density ($\Shtwo\gtrsim$20 \msunpc) regions of the disks to minimize the contribution from diffuse extended emission, we find an approximately linear relation between molecular gas and star formation rate surface density, $\nmol\sim0.96\pm0.16$, with a molecular gas depletion time $\tdep\sim2.30\pm1.32$ Gyr. We show that, in the molecular regions of our galaxies there are no clear correlations between \tdep\ and the free-fall and effective Jeans dynamical times throughout the sample. We do not find strong trends in the power-law index of the spatially resolved molecular gas star formation law or the molecular gas depletion time across the range of galactic stellar masses sampled (\mstar $\sim$$10^{9.7}-10^{11.5}$ \msun). There is a trend, however, in global measurements that is particularly marked for low mass galaxies. We suggest this trend is probably due to the low surface brightness CO, and it is likely associated with changes in CO-to-H2 conversion factor.

The global star formation law of galaxies revisited in the radio continuum

We study the global star formation law, the relation between the gas and star formation rate (SFR) in a sample of 130 local galaxies with infrared (IR) luminosities spanning over three orders of magnitude (109–1012 L⊙), which includes 91 normal spiral galaxies and 39 (ultra)luminous IR galaxies [(U)LIRGs]. We derive their total (atomic and molecular) gas and dense molecular gas masses using newly available HI, CO and HCN data from the literature. The SFR of galaxies is determined from total IR (8–1000 μm) and 1.4 GHz radio continuum (RC) luminosities. The galaxy disk sizes are defined by the de-convolved elliptical Gaussian FWHM of the RC maps. We derive the galaxy disk-averaged SFRs and various gas surface densities, and investigate their relationships. We find that the galaxy disk-averaged surface density of dense molecular gas mass has the tightest correlation with that of SFR (scatter ∼0.26 dex), and is linear in log-log space (power-law slope of N=1.03±0.02) across the full galaxy sample. The correlation between the total gas and SFR surface densities for the full sample has a somewhat larger scatter (∼0.48 dex), and is best fit by a power-law with slope 1.45±0.02. However, the slope changes from ∼1 when only normal spirals are considered, to ∼1.5 when more and more (U)LIRGs are included in the fitting. When different CO-to-H2 conversion factors are used to infer molecular gas masses for normal galaxies and (U)LIRGs, the bi-modal relations claimed recently in CO observations of high-redshift galaxies appear to also exist in local populations of star-forming galaxies.

The ISM in Distant Galaxies

The interstellar medium (ISM) is a key ingredient in galaxy formation and evolution as it provides the molecular gas reservoir which fuels star formation and supermassive black hole accretion. Yet the ISM is one of the least studied aspects of distant galaxies. Molecular and atomic transitions at (sub)millimetre wavelengths hold great promise in measuring macroscopic properties (e.g. masses, morphologies, star formation laws), as well as microscopic properties (e.g. gas densities, temperatures, cooling) of high-z galaxies. In this overview I summarize the growing number of high-z molecular line detections, highlighting some of the most intriguing results along the way. I end by discussing a few areas where future facilities (e.g. ALMA, EVLA, CCAT, LMT) will drastically improve on the current state of affairs.

A UNIVERSAL, LOCAL STAR FORMATION LAW IN GALACTIC CLOUDS, NEARBY GALAXIES, HIGH-REDSHIFT DISKS, AND STARBURSTS

[abridged] While observations of Local Group galaxies show a very simple, local star formation law in which the star formation rate per unit area in each patch of a galaxy scales linearly with the molecular gas surface density, recent observations of both Milky Way molecular clouds and high redshift galaxies apparently show a more complicated relationship, in which regions of equal surface density can form stars at quite different rates. These data have been interpreted as implying either that different star formation laws apply in different circumstances, that the star formation law is sensitive to large-scale galaxy properties rather than local properties, or that there are high density thresholds for star formation. Here we collate resolved observations of Milky Way molecular clouds, kpc-scale observations of Local Group galaxies, and unresolved observations of both disk and starburst galaxies in the local universe and at high redshift. We show that all of these data are in fact consistent with a simple, local, volumetric star formation law. The apparent variations stem from the fact that the observed objects have a wide variety of 3D size scales and degrees of internal clumping, so even at fixed gas column density the regions being observed can have wildly varying volume densities. We provide a simple theoretical framework to remove this projection effect, and we show that all the data, from small Solar neighborhood clouds with masses ~10^3 Msun to sub-mm galaxies with masses ~10^11 Msun, fall on a single star formation law in which the SFR is simply ~1% of the molecular gas mass per local free-fall time. In contrast, proposed star formation laws in which the star formation timescale is set by the galactic rotation period or the SFR is linearly proportional to the gas mass above some density threshold fail to match at least some of the data.

The Influence of the Residual Mg Content in the Ductile Cast Iron on the Formation Law of Spherodial Graphite

The residual Mg content ,spherodize ratio and nuclei of spherodial graphites(abbreviated SG) were studied by casting a series of similar composition ductile iron rods and white samples with different holding time of spheroidizing. The results indicate that the residual Mg content in the ductile iron was less and less as the holding time grows ,which causing the morphology of graphites transfer from spherodial to oval. Spherodize ratio change law is not continuous as increasing the residual Mg content which is divided at the 0.02%. The morphologies of nuclei of SGs core are typical examples of the highly magnified structure of spherical and irregular polygons; the diameters are about 0.5~2μm, consisting of (Mg, Ca)S along with CeO2and MgO. Disregistry δ between the nucleus compounds and graphite are low,which indicates that nucleus compounds are good nucleating site for SGs.The Mg element in nuclei of SG just act as nucleation substrates.it is the Mg which maybe simple substance in the metallic matrix that act as the role of spherodizer determines the graphite shape.

The Influence of Straw Shape on the Deposit Formation during Straw Briquette Combustion

During the combustion of straw, the formation of deposits, which erode the heating surface of furnace and affects the safe operation, is influenced by many factors. This paper studies the influences of straw shape on the deposit formation. The result is as follows. The shape of fuel affects the process of combustion, accordingly, it affects the formation law and properties of deposits. Firstly, the change law of deposition rate is different from the combustion of native straw; secondly, the deposition rate and amount are significantly lower than that produced by the native straw; at last, the shape of fuel has an important influence on the characteristics and component of deposit.

Study on Mathematical Simulation of Nitrogen Oxides (NO<sub>x</sub>) Formation of Coal-Fired Boiler

There exist certain limitations to research the law and influence factors of the nitrogen oxides formation only with the help of field tests, because the nitrogen oxides formation of the boiler is influenced by various factors. The flow, combustion mathematical models interrelated and so on are established taking the 410t/h boiler fired tangentially as a prototype by the use of the fluent software. All the mathematical models are verified and modified with the aid of routine field test data, and the accuracy and reliability of the mathematical models are improved. Then NOx formation performance is stimulated in allusion to the influence factors without field test conditions. The mathematical simulation results show that mathematical models can provide a sufficient theoretical basis to analyze accurately combustion and NOx formation law in furnace, and the deficiencies of field tests have been made up.

WHEELS OF FIRE. IV. STAR FORMATION AND THE NEUTRAL INTERSTELLAR MEDIUM IN THE RING GALAXY AM0644-741

We combine data from the ATNF and the SEST to investigate the neutral ISM in AM0644-741, a large and robustly star-forming ring galaxy. The galaxy's ISM is concentrated in the 42-kpc diameter starburst ring, but appears dominated by atomic gas, with a global molecular fraction (f_mol) of only 7.9%. Apart from the starburst peak, the gas ring is stable against the growth of gravitational instabilities (Q_gas=2-7). Including stars lowers Q overall, but not enough to make Q<1 everywhere. The ring's global star formation efficiency (SFE) appears somewhat elevated, but varies around the ring by more than an order of magnitude, peaking where star formation is most intense. AM0644-741's star formation law is peculiar: HI follows a Schmidt law while H2 is uncorrelated with SFR/area. Photodissociation models yield low volume densities in the ring, particularly in the starburst quadrant (n~2 cm^-3), implying a warm neutral medium dominated ISM. At the same time, the ring's pressure and ambient far-ultraviolet radiation field lead to the expectation of a predominantly molecular ISM. We argue that the ring's peculiar star formation law, n, SFE, and f_mol result from the ISM's >100 Myr confinement time in the starburst ring, which enhances the destructive effects of embedded massive stars and supernovae. As a result, the ring's molecular ISM becomes dominated by small clouds where star formation is most intense, causing H2 to be underestimated by 12CO line fluxes: in effect X(CO) >> X(Gal) despite the ring's solar metallicity. The observed large HI component is primarily a low density photodissociation product, i.e., a tracer rather than a precursor of massive star formation. Such an "over-cooked" ISM may be a general characteristic of evolved starburst ring galaxies.

A CORRELATION BETWEEN SURFACE DENSITIES OF YOUNG STELLAR OBJECTS AND GAS IN EIGHT NEARBY MOLECULAR CLOUDS

We report the discovery and characterization of a power law correlation between the local surface densities of Spitzer-identified, dusty young stellar objects and the column density of gas (as traced by near-IR extinction) in eight molecular clouds within 1 kpc and with 100 or more known YSOs. This correlation, which appears in data smoothed over size scales of ~1 pc, varies in quality from cloud to cloud; those clouds with tight correlations, MonR2 and Ophiuchus, are fit with power laws of slope 2.67 and 1.87, respectively. The spread in the correlation is attributed primarily to local gas disruption by stars that formed there or to the presence of very young sub-regions at the onset of star formation. We explore the ratio of the number of Class II to Class I sources, a proxy for the star formation age of a region, as a function of gas column density; this analysis reveals a declining Class II to Class I ratio with increasing column density. We show that the observed star-gas correlation is consistent with a star formation law where the star formation rate per area varies with the gas column density squared. We also propose a simple picture of thermal fragmentation of dense gas in an isothermal, self-gravitating layer as an explanation for the power law. Finally, we briefly compare the star gas correlation and its implied star formation law with other recent proposed of star formation laws at similar and larger size scales from nearby star forming regions.

The Formation Laws and Influencing Factors of Strengthening Layer in EDM of Stainless Steel 1Cr13

For the abrasion phenomenon of the turbine flowing-passage components was very serious, the electrical discharge machining (EDM) surface strengthening process of stainless steel 1Cr13 by different electrodes were carried out in this paper, the formation laws and influencing factors of the EDM surface strengthening layer are researched deeply. The correspondence relation between strengthening layer thickness and enhancing time, electrode materials, and electrical parameters are obtained by the detailed theoretical analysis and experimental investigation. The results show that, in the premise of the strengthening layer thickness, workpiece quality and machining efficiency, the strengthening process can be improved by reasonable selecting and controlling the process parameters such as discharge voltage, capacitance, pulse frequency, peak current, pulse width and enhancing time.

What triggers star formation in galaxies?

AbstractProcesses that promote the formation of dense cold clouds in the interstellar media of galaxies are reviewed. Those that involve background stellar mass include two-fluid instabilities, spiral density wave shocking, and bar accretion. Young stellar pressures trigger gas accumulation on the periphery of cleared cavities, which often take the form of rings by the time new stars form. Stellar pressures also trigger star formation in bright-rim structures, directly squeezing the pre-existing clumps in nearby clouds and clearing out the lower density gas between them. Observations of these processes are common. How they fit into the empirical star formation laws, which relate the star formation rate primarily to the gas density, is unclear. Most likely, star formation follows directly from the formation of cold dense gas, whatever the origin of that gas. If the average pressure from the weight of the gas layer is large enough to produce a high molecular fraction in the ambient medium, then star formation should follow from a variety of processes that combine and lose their distinctive origins. Pressurized triggering might have more influence on the star formation rate in regions with low average molecular fraction. This implies, for example, that the arm/interarm ratio of star formation efficiency should be higher in the outer regions of galaxies than in the main disks.

On the impact of empirical and theoretical star formation laws on galaxy formation

We investigate the consequences of applying different star formation laws in the galaxy formation model GALFORM. Three broad star formation laws are implemented: the empirical relations of Kennicutt and Schmidt and Blitz & Rosolowsky and the theoretical model of Krumholz, McKee & Tumlinson. These laws have no free parameters once calibrated against observations of the star formation rate (SFR) and gas surface density in nearby galaxies. We start from published models, and investigate which observables are sensitive to a change in the star formation law, without altering any other model parameters. We show that changing the star formation law (i) does not significantly affect either the star formation history of the universe or the galaxy luminosity functions in the optical and near-IR, due to an effective balance between the quiescent and burst star formation modes; (ii) greatly affects the cold gas contents of galaxies; (iii) changes the location of galaxies in the SFR versus stellar mass plane, so that a second sequence of "passive" galaxies arises, in addition to the known "active" sequence. We show that this plane can be used to discriminate between the star formation laws.

FEEDBACK-REGULATED STAR FORMATION: IMPLICATIONS FOR THE KENNICUTT-SCHMIDT LAW

We derive a metallicity dependent relation between the surface density of the star formation rate (Sigma_{SFR}) and the gas surface density (Sigma_{g}) in a feedback regulated model of star formation in galactic disks. In this model, star formation occurs in gravitationally bound protocluster clumps embedded in larger giant molecular clouds with the protocluster clump mass function following a power law function with a slope of -2. Metallicity dependent feedback is generated by the winds of OB stars (M > 5 Msol) that form in the clumps. The quenching of star formation in clumps of decreasing metallicity occurs at later epochs due to weaker wind luminosities, thus resulting in higher final star formation efficiencies (SFE_{exp}). By combining SFE_{exp} with the timescales on which gas expulsion occurs, we derive the metallicity dependent star formation rate per unit time in this model as a function of Sigma_{g}. This is combined with the molecular gas fraction in order to derive the global dependence of Sigma_{SFR} on Sigma_{g}. The model reproduces very well the observed star formation laws extending from low gas surface densities up to the starburst regime. Furthermore, our results show a dependence of $\Sigma_{SFR}$ on metallicity over the entire range of gas surface densities in contrast to other models, and can also explain part of the scatter in the observations. We provide a tabulated form of the star formation laws that can be easily incorporated into numerical simulations or semi-analytical models of galaxy formation and evolution.

STAR FORMATION IN THE EXTENDED GASEOUS DISK OF THE ISOLATED GALAXY CIG 96

We study the Kennicutt-Schmidt star formation law and efficiency in the gaseous disk of the isolated galaxy CIG 96 (NGC 864), with special emphasis on its unusually large atomic gas (HI) disk (r_HI/r_25 = 3.5, r_25 = 1.'85). We present deep GALEX near and far ultraviolet observations, used as a recent star formation tracer, and we compare them with new, high resolution (16", or 1.6 kpc) VLA HI observations. The UV and HI maps show good spatial correlation outside the inner 1', where the HI phase dominates over H_2. Star-forming regions in the extended gaseous disk are mainly located along the enhanced HI emission within two (relatively) symmetric giant gaseous spiral arm-like features, which emulate a HI pseudo-ring at a r \simeq 3' . Inside such structure, two smaller gaseous spiral arms extend from the NE and SW of the optical disk and connect to the previously mentioned HI pseudo-ring. Interestingly, we find that the (atomic) Kennicutt-Schmidt power law index systematically decreases with radius, from N \simeq 3.0 +- 0.3 in the inner disk (0.'8 - 1.'7) to N = 1.6 +- 0.5 in the outskirts of the gaseous disk (3.'3 - 4.'2). Although the star formation efficiency (SFE), the star formation rate per unit of gas, decreases with radius where the HI component dominates as is common in galaxies, we find that there is a break of the correlation at r = 1.5 r_25. At radii 1.5 r_25 < r < 3.5 r_25, mostly within the HI pseudo-ring structure, there exist regions whose SFE remains nearly constant, SFE \simeq 10^-11 yr^-1. We discuss about possible mechanisms that might be triggering the star formation in the outskirts of this galaxy, and we suggest that the constant SFE for such large radii r > 2 r_25 and at such low surface densities might be a common characteristic in extended UV disk galaxies.

The effect of variations in the input physics on the cosmic distribution of metals predicted by simulations

[Abridged] We investigate how a range of physical processes affect the cosmic metal distribution using a suite of cosmological, hydrodynamical simulations. Focusing on z = 0 and 2, we study the metallicities and metal mass fractions for stars as well as for the ISM, and several more diffuse gas phases. We vary the cooling rates, star formation law, structure of the ISM, galactic winds, feedback from AGN, reionization history, stellar IMF, and cosmology. In all models stars and the warm-hot IGM (WHIM) constitute the dominant repository of metals, while for z > 2 the ISM is also important. In models with galactic winds, predictions for the metallicities of the various phases vary at the factor of two level and are broadly consistent with observations. The exception is the cold-warm IGM, whose metallicity varies at the order of magnitude level if the prescription for galactic winds is varied, even for a fixed wind energy per unit stellar mass formed, and falls far below the observed values if winds are not included. At the other extreme, the metallicity of the intracluster medium (ICM) is largely insensitive to the presence of galactic winds, indicating that its enrichment is regulated by other processes. The mean metallicities of stars (~ Z_sun), the ICM (~ 0.1 Z_sun), and the WHIM (~ 0.1 Z_sun) evolve only slowly, while those of the cold halo gas and the IGM increase by more than an order of magnitude from z = 5 to 0. Higher velocity outflows are more efficient at transporting metals to low densities, but actually predict lower metallicities for the cold-warm IGM since the winds shock-heat the gas to high temperatures, thereby increasing the fraction of the metals residing in, but not the metallicity of, the WHIM. Besides galactic winds driven by feedback from star formation, the metal distribution is most sensitive to the inclusion of metal-line cooling and feedback from AGN.

CARMA SURVEY TOWARD INFRARED-BRIGHT NEARBY GALAXIES (STING): MOLECULAR GAS STAR FORMATION LAW IN NGC 4254

This study explores the effects of different assumptions and systematics on the determination of the local, spatially resolved star formation law. Using four star formation rate (SFR) tracers (H\alpha with azimuthally averaged extinction correction, mid-infrared 24 micron, combined H\alpha and mid-infrared 24 micron, and combined far-ultraviolet and mid-infrared 24 micron), several fitting procedures, and different sampling strategies we probe the relation between SFR and molecular gas at various spatial resolutions and surface densities within the central 6.5 kpc in the disk of NGC4254. We find that in the high surface brightness regions of NGC4254 the form of the molecular gas star formation law is robustly determined and approximately linear and independent of the assumed fraction of diffuse emission and the SFR tracer employed. When the low surface brightness regions are included, the slope of the star formation law depends primarily on the assumed fraction of diffuse emission. In such case, results range from linear when the fraction of diffuse emission in the SFR tracer is ~30% or less (or when diffuse emission is removed in both the star formation and the molecular gas tracer), to super-linear when the diffuse fraction is ~50% and above. We find that the tightness of the correlation between gas and star formation varies with the choice of star formation tracer. The 24 micron SFR tracer by itself shows the tightest correlation with the molecular gas surface density, whereas the H\alpha corrected for extinction using an azimuthally-averaged correction shows the highest dispersion. We find that for R<0.5R_25 the local star formation efficiency is constant and similar to that observed in other large spirals, with a molecular gas depletion time ~2 Gyr.

편대 유도 법칙 및 초소형 비행체의 자동 편대 비행 구현

본 논문에서는 초소형 비행체의 자동 편대 비행을 위한 유도 법칙과 비행 시험 결과를 기술하였다. 초소형 비행체는 탑재 중량과 비행시간 등의 제한으로 인해 짧은 시간 안에 복수의 비행체가 임무를 분담하거나 협력하여 동시에 수행하는 것이 효율적이며 편대 비행은 이러한 임무 하중을 효과적으로 감소시킬 수 있다. 제안된 편대 유도 법칙은 Leader-Follower 편대 비행의 기하학적 관계 기반으로 비선형 모델 역변환 기법을 이용하여 설계하였다. 편대 유도 법칙에 필요한 비행체의 상태 정보는 비행체 간 고속의 데이터 통신 시스템을 구성하고 지상국을 통해 송수신하도록 하였다. 본 연구에서 제안된 비행체간 통신 기반의 편대 유도 기법은 센서의 측정 잡음에 대한 강건한 성능을 확인하기 위해 실제 비행 데이터 기반 시뮬레이션을 수행하였고 다수의 초소형 비행체를 이용한 편대 비행 시험을 통해 유도 법칙의 타당성을 검증하고 확인하였다. This paper presents an autonomous formation flight algorithm for micro aerial vehicles (MAVs) and its flight test results. Since MAVs have severe limits on the payload and flight time, formation of MAVs can help alleviate the mission load of each MAV by sharing the tasks or coverage areas. The proposed formation guidance law is designed using nonlinear dynamic inversion method based on 'Leader-Follower' formation geometric relationship. The sensing of other vehicles in a formation is achieved by sharing the vehicles' states using a high-speed radio data link. the designed formation law was simulated with flight data of MAV to verify its robustness against sensor noises. A series of test flights were performed to validate the proposed formation guidance law. The test result shows that the proposed formation flight algorithm with inter-communication is feasible and yields satisfactory results.

THE PRESENCE OF "DAMNATIO MEMORIAE" IN ROMAN ART

Previous articleNext article No AccessTHE PRESENCE OF "DAMNATIO MEMORIAE" IN ROMAN ARTLauren Hackworth PetersenLauren Hackworth Petersen Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by Source Volume 30, Number 2Winter 2011 Sponsored by the Bard Graduate Center, New York Article DOIhttps://doi.org/10.1086/sou.30.2.23208566 Views: 185Total views on this site Citations: 2Citations are reported from Crossref © 2011 Ars Brevis Foundation Inc.PDF download Crossref reports the following articles citing this article:Ayelet Haimson Lushkov Not cricket, not classics? A case study in the limits of reception, Classical Receptions Journal 13, no.44 (Jun 2021): 555–570.https://doi.org/10.1093/crj/claa022Mateusz Maria Bieczyński The History of Artistic Freedom as a Legal Standard in Western Culture: An Attempt at Periodization of the Process of Its Formation, Santander Art and Culture Law Review 7, no.11 (Dec 2021): 145–170.https://doi.org/10.4467/2450050XSNR.21.010.14599

Star Formation on Galactic Scales: Empirical Laws

Empirical star formation laws from the last 20 years are reviewed with a comparison to simulations. The current form in main galaxy disks has a linear relationship between the star formation rate per unit area and the molecular cloud mass per unit area with a timescale for molecular gas conversion of about 2 Gyr. The local ratio of molecular mass to atomic mass scales nearly linearly with pressure, as determined from the weight of the gas layer in the galaxy. In the outer parts of galaxies and in dwarf irregular galaxies, the disk can be dominated by atomic hydrogen and the star formation rate per unit area becomes directly proportional to the total gas mass per unit area, with a consumption time of about 100 Gyr. The importance of a threshold for gravitational instabilities is not clear. Observations suggest such a threshold is not always important, while simulations generally show that it is. The threshold is difficult to evaluate because it is sensitive to magnetic and viscous forces, the presence of spiral waves and other local effects, and the equation of state.

Molecular gas and star formation in early-type galaxies

We present new mm interferometric and optical integral-field unit (IFU) observations and construct a sample of 12 elliptical (E) and lenticular (S0) galaxies with molecular gas which have both CO and optical maps. The galaxies contain 2 × 107 to 5 × 109 M⊙ of molecular gas distributed primarily in central discs or rings (radii 0.5–4 kpc). The molecular gas distributions are always coincident with distributions of optically obscuring dust that reveal tightly wound spiral structures in many cases. The ionized gas always approximately corotates with the molecular gas, evidencing a link between these two gas components, yet star formation is not always the dominant ionization source. The galaxies with less molecular gas tend to have [O iii]/Hβ emission-line ratios at high values not expected for star formation. Most E/S0s with molecular gas have young or intermediate-age stellar populations based on optical colours, ultraviolet colours and absorption linestrengths. The few that appear purely old lie close to the limit where such populations would be undetectable based on the mass fractions of expected young to observed old stars. The 8 μm polycyclic aromatic hydrocarbon (PAH) and 24 μm emission yield similar star formation rate (SFR) estimates of E/S0s, but the total infrared overpredicts the rate due to a contribution to dust heating from older stars. The radio–far-infrared relation also has much more scatter than for other star-forming galaxies. However, despite these biases and additional scatter, the derived star formation rates locate the E/S0 galaxies within the large range of the Schmidt–Kennicutt and constant efficiency star formation laws. Thus, the star formation process in E/S0s is not overwhelmingly different than in other star-forming galaxies, although one of the more reliable tracers (24 μm) points to a possible lower star formation efficiency at a given gas surface density.