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young star clusters are potentially bright , long lived , tracers of star formation within their host galaxies . it is therefore of paramount importance to understand what governs the cluster formation process ( e.g. , * ? ? ? * ) and how the host galactic environment may affect their formation and evolution ( e.g. , * ? ? ? statistically we can describe the cluster formation as a stochastic process . numerous works report of an initial cluster mass and luminosity function ( icmf and iclf , respectively ) being described with good approximation by a single power - law slope of index close to @xmath3 . the stochastic nature of cluster formation combined with the power - law distributions of the cluster mass generate the so called size - of - sample effects . these effects are well described by the positive relations between the number of clusters @xcite or the youngest brightest cluster in v band , m@xmath8 , versus the galactic star formation rate ( sfr ; * ? ? ? * ; * ? ? ? in other words , galaxies with higher sfr have more numerous cluster populations , therefore they are more likely to sample the icmf at higher mass ( luminosity ) ranges . the size - of - sample effect also applies to the time - binning of the cluster population . massive clusters are statistically more likely to be older because the galaxy has had a longer period of time to sample the high mass bins of the icmf @xcite . increasing evidence , however , suggests that this is not the full picture . a steepening at the bright luminosity bins of the iclf has widely been observed and reported . this steepening could be explained by the presence of a truncation at the high mass end of the icmf . indeed , the presence of a truncation mass may explain why we do not observe very massive young star clusters close to @xmath9 mass in the milky way @xcite . however , it is difficult to establish the presence of a truncation due to low number statistics @xcite . several works report an icmf compatible with a schechter function of slope @xmath3 , and an exponential cutoff at masses above a certain characteristic mass , . interestingly it has been observed by these authors that may change as function of the host galactic environment . such an environmental dependence would be expected theoretically due to the variation of the maximum mass scale for gravitational instability in galaxy discs ( the `` toomre mass '' , toomre 1964 ) , which should lead to an increase of the maximum cluster mass with the gas pressure ( kruijssen 2014 ) . more evidence of the role played by the galactic environment on the properties of their cluster population has indirectly been suggested by the so called t@xmath10(u ) versus sfr relation @xcite . t@xmath10(u ) is the fraction of u band light locked in star clusters with respect to the total u band light of the galaxy . this fraction is observed to increase as function of the sfr of the galaxy , suggesting that the fraction of star formation happening in clusters ( hereafter or cluster formation efficiency , cfe ) is increasing @xcite . indeed direct evidence of a varying cfe as function of the average galactic star formation rate density ( @xmath11 ) has been observed in numerous galaxies ( e.g. , * ? ? ? * ; * ? ? ? * ; * ? ? ? * ; * ? ? ? * among many others ) .    in the model proposed by @xcite a variation in the cfe is directly linked to the star and cluster formation process itself . this model describes star and cluster formation continuously across the density spectrum of the hierarchically structured ism , in which the highest star formation efficiencies ( and thus bound stellar fractions ) are reached in the highest density peaks . integration of these local physics over the gas density spectrum then results in a cfe that increases with the gas surface density or pressure , as well as the sfr density ( kruijssen 2012 ) . given the density gradient observed in disc galaxies , the model thus predicts that the cfe decreases with the galactocentric radius . indeed , using a small fraction of the whole cluster population of m83 , ( * ? ? ? * hereafter sv13 ) report evidence of such a variation of the cfe as function of galactocentric distances . the aim of this article is to probe the imprints that the galactic environment leaves on the properties of its cluster population . the results will shed light on how the star cluster population is a natural outcome of the physics driving galactic star formation , and will also help to use star cluster populations as tracers of the sfh of their host galaxies . to achieve this goal we study the cluster population of the nearby ( @xmath12 mpc , corresponding to a distance modulus of 28.28 mag ) spiral galaxy m83 . this galaxy hosts a rich cluster population which has been widely analysed in recent years . several studies suggest that the current ongoing starburst at the centre of this galaxy ( e.g. , * ? ? ? * ) was mostly likely produced by a recent minor merger @xcite . outside this region the most active star - forming regions in the galaxy are at the end of the bar ( see figure  [ fig : m83 ] ) . however , we notice that star formation is occurring over the entire spiral arm system and in spurs extended inside the inter - arm regions , as in m51 @xcite .    only recently m83 has been fully observed with the hubble space telescope ( hst ) with broad and narrow imaging bands covering from the @xmath13 to the @xmath14 and several optical emission lines @xcite . previous studies of the cluster population have therefore focused on the two pointings f1 and f2 ( see figure  [ fig : m83 ] ) . @xcite report of a similar icmf and cluster disruption rate in both inner ( f1 ) and outer ( f2 ) fields . they notice a steepening of the icmf slope and a milder disruption rate in f2 , but they conclude that within the uncertainties the results support a cluster formation and evolution scenario independent of the galactic environment . with a similar cluster catalogue ( comparison presented in both @xcite ) , ( * ? ? ? * ; * ? ? ? * hereafter b12 ) point out the differences in the photometric properties , icmf and iclf , disruption rate of the cluster populations in the two pointings . the differences can not be accounted for by a recent , significant change in the sfh , so are therefore most likely linked to the cluster formation and disruption properties of the local galactic environment . such a change in cluster properties is also supported by the change in the cfe as function of distance from the centre of the galaxy observed by sv13 . the access to a full cluster catalogue for m83 now allows us to verify and put stronger constraints on previous findings . using the whole m83 cluster catalogue , ( * * hereafter sv14 ) find a clear environmental dependency on the strength of the cluster disruption with higher cluster disruption in the inner regions of the galaxy , as already suggested by b12 . in a recent publication , @xcite has studied the h@xmath15 morphology of the very young star clusters in m83 , reporting that clusters are already partially or fully exposed within a few myr after their formation . ryon et al ( 2015 ) has focused on the analysis of m83 cluster sizes , important for the dynamical evolution of these systems . in the present work we will expand the icmf analysis published by b12 and the analysis of the cfe by sv13 to the whole cluster population within the m83 disk . all together , these works are presenting an unprecedentedly detailed and complete study of the cluster population of a nearby galaxy . the paper is organised as follows . section 2 describes the photometric analysis and the properties of the final cluster catalogue . we also include a description of the ancillary data used in the analysis . in section 3 , we present our results . section 4 contains a discussion of the results within the wider context of cluster and star formation in galaxies . a summary of the paper is presented in the conclusions ( section 5 ) . this analysis is based on the complete m83 cluster catalogue recently published in sv14 . the final cluster catalogue has been obtained from two multi - band hst imaging datasets , ( go 11360 , pi : oconnell , and go 12513 , pi : blair ) . the two combined datasets cover within 7 pointings the face - on m83 disk up to a distance of 4.5 kpc ( 3.4 ) from the centre of the galaxy ( see figure  [ fig : m83 ] and table  [ tab1 ] ) . our analysis is based on wfc3 imaging in 5 optical bands , f336w ( hereafter @xmath16 band ) , f438w ( @xmath17 band ) , f555w or f547 m ( @xmath18 band ) , f657n ( narrow filter centred on h@xmath15 ) , and f814w ( hereafter @xmath19 band ) . cluster detection has been performed on the v band with optimised parameter inputs of the source extraction algorithm sextractor . for each extracted source , aperture photometry has been performed in all the bands with an aperture radius of 5 px ( 0.2@xmath20 4.4 pc ) and a sky annulus located at 8 px ( 0.32 ) and 2 px ( 0.08 ) wide . isolated compact clusters , visually selected , were used to estimate and add the amount of missed flux lost because of the small aperture size used . moreover small differences in calibration between different pointings were corrected as explained in sv14 . the final catalogue retains only sources with a concentration index larger than 1.25 mag and positive detections in 4 filters ( @xmath21 ) . we consider detection in h@xmath15 as additional but not required constraint . the vega zero points used to flux calibrate the photometry have been retrieved from the wfc3 instrument webpage . milky way foreground extinction correction has been applied @xcite . as described in sv14 , the initial catalogue has been visually inspected and each source has been assigned a flag describing the morphology of the cluster . class 1 objects are clusters with symmetric and compact light distribution . class 1 objects are most likely bound clusters as tested in b12 . class 2 objects show asymmetries in the light distribution , multiple peaks , potentially contaminant neighbours . these objects closely resemble ob associations , therefore there is a fair chance of them being unbound @xcite . class 3 objects are spurious detections ( bad pixels mostly located at the end of the chip , background and foreground sources ) and have been removed from the final catalogue . any cluster candidate located within a radius of 0.45 kpc has also been excluded from the catalogue . we excluded this region because of the high luminosity gradient which causes a change in the completeness of the cluster detection and because of the different sfh that this region has experienced ( b12 ) . the number of cluster candidates detected in each field is listed in table  [ tab1 ] .           + galaxy & m@xmath8 & sfr & @xmath11 & + & [ mag ] & m@xmath22yr@xmath23&m@xmath22yr@xmath23kpc@xmath24 & % + m82@xmath25 & -14.80 & 7.00 &  &  + ngc3597@xmath25 & -13.30 & 10.80 &  &  + iras19115@xmath25 & -16.80 & 192.00 &  &  + ngc1533@xmath25 ( a1 ) & -7.17 & 0.37@xmath26 &  &  + ngc1533@xmath25 ( a2 ) & -5.71 & 0.25@xmath26 &  &  + ngc1533@xmath25 ( a3 ) & -6.16 & 0.18@xmath26 &  &  + ngc2623@xmath25 & -14.50 & 51.00 &  &  + ngc3256@xmath25 & -15.70 & 46.00 & 0.62 & 22.9@xmath27@xmath28 + ngc7673@xmath25 & -14.70 & 4.90 &  &  + ngc6745@xmath25 & -15.00 & 12.20 &  &  + ngc1140@xmath25 & -14.80 & 0.80 &  &  + milky way@xmath28 &  & 0.1508 & 0.012 & 7.0@xmath29 + ngc45@xmath30 & -10.83 & 0.12 &  &  + ngc45@xmath31 &  & 0.05 & 1.02@xmath26 & 5.2@xmath320.3 + ngc406@xmath30 & -11.75 & 0.29 &  &  + ngc628@xmath30 & -11.84 & 0.23 &  &  + ngc1300@xmath30 ( f1 ) & -11.00 & 0.30 &  &  + ngc1300@xmath30 ( f2 ) & -11.52 & 0.32 &  &  + ngc1309@xmath30 & -13.80 & 1.70 &  &  + ngc1313@xmath30 & -10.98 & 0.22 &  &  + ngc1313@xmath31 &  & 0.68 & 0.011 & 3.2@xmath320.2 + ngc1483@xmath30 & -10.01 & 0.11 &  &  + ngc3627@xmath30 & -11.97 & 0.37 &  &  + ngc4038@xmath30 & -15.25 & 2.43 &  &  + ngc4394@xmath30 & -10.25 & 0.14 &  &  + ngc4395@xmath30 & -9.79 & 0.07 &  &  + ngc4395@xmath31 &  & 0.17 & 4.66@xmath26 & 1.0@xmath320.6 + ngc4736@xmath30 & -10.44 & 0.04 &  &  + ngc5055@xmath30 & -9.61 & 0.02 &  &  + m101@xmath30 ( f1 ) & -11.38 & 0.25 &  &  + m101@xmath30 ( f2 ) & -11.57 & 0.20 &  &  + ngc6503@xmath30 & -10.51 & 0.07 &  & + ngc7793@xmath30 & -9.65 & 0.07 &  & + ngc7793@xmath31 &  & 0.15 & 6.51@xmath26 & 2.5@xmath320.3 + ngc4449@xmath33 & -12.60 & 1.0 & 0.04 & 9.0 + ngc1569 & -13.9@xmath34 & 0.36@xmath35 & 0.03@xmath35 & 13.9@xmath36 + ngc1705@xmath37 & -13.8 & 0.31 & 0.046 &  + smc@xmath38 & -9.94 & 0.043 & 0.001 & 4.2@xmath39@xmath28 + he2 - 10@xmath40 & -12.5 & 0.20 & 0.20 &  + ngc2366@xmath41 & -8.52 & 0.094 & 2.4@xmath26 &  + ugc4305@xmath41 & -8.88 & 0.114 & 2.2@xmath26 &  + ugc4459@xmath41 & -7.9 & 0.003 & 1.0@xmath26 &  + ugc5336@xmath41 & -8.59 & 0.004 & 0.00037 &  + ic2574@xmath41 & -9.12 & 0.11 & 1.2@xmath26 &  + ugc5692@xmath41 & -9.44 & 7.34@xmath26 & 0.5@xmath26 &  + ugca292@xmath41 & -7.46 & 5.15@xmath26 & 0.01 &  + ugc8201@xmath41 & -9.16 & 31.6@xmath26 & 2.1@xmath26  & + ugc9128@xmath41 & -5.45 & 0.3@xmath26 & 0.3@xmath26 &  + ugc9240@xmath41 & -5.90 & 5.24@xmath26 & 1.0@xmath26 &  + dwarf sample@xmath42 &  &  & [ 0.01 , 10.0]@xmath26 & 5.0 + ic10@xmath43 & -10.4 & 0.07 & 0.03 & 4.2 +
we present a study of the m83 cluster population , covering the disc of the galaxy between radii of 0.45 and 4.5 kpc . 
 we aim to probe the properties of the cluster population as a function of distance from the galactic centre . 
 we observe a net decline in cluster formation efficiency ( , i.e. the amount of star formation happening in bound clusters ) from about 26% in the inner region to 8% in the outer part of the galaxy . 
 the recovered values within different regions of m 83 follow the same versus star formation rate density relation observed for entire galaxies . 
 we also probe the initial cluster mass function ( icmf ) as a function of galactocentric distance . 
 we observe a significant steepening of the icmf in the outer regions ( from @xmath0 to @xmath1 ) and for the whole galactic cluster population ( slope of @xmath2 ) of m83 . 
 we show that this change of slope reflects a more fundamental change of the truncation mass at the high - mass end of the distribution . 
 this can be modelled as a schechter function of slope @xmath3 with an exponential cut - off mass ( @xmath4 ) that decreases significantly from the inner to the outer regions ( from 4.00 to @xmath5 ) while the galactic is @xmath6 . 
 the trends in and icmf are consistent with the observed radial decrease of the @xmath7 , hence in gas pressure . 
 as gas pressure declines cluster formation becomes less efficient . 
 we conclude that the host galaxy environment appears to regulate 1 ) the fraction of stars locked in clusters ; 2 ) the upper mass limit of the icmf , consistently described by a near - universal slope @xmath3 truncated at the high - mass end .    [ firstpage ]    galaxies : spiral  galaxies : star clusters  galaxies : star formation  star : formation