Pulsars_NN2 as_II the_AT Sources_NN2 of_IO High_JJ Energy_NN1 Cosmic_JJ Ray_NP1 Positrons_NP1 1_MC1 Introduction_NN1 Dark_NN1 matter_NN1 particles_NN2 annihilating_VVG in_II the_AT Galactic_JJ Halo_NN1 are_VBR predicted_VVN to_TO generate_VVI a_AT1 number_NN1 of_IO potentially_RR observable_JJ products_NN2 ,_, including_II gamma-rays_NN2 ,_, electrons_NN2 ,_, positrons_NN2 ,_, protons_NN2 and_CC antiprotons_NN2 ._. 
In_II contrast_NN1 to_II gamma-rays_NN2 ,_, which_DDQ travel_VV0 along_RP straight_JJ lines_NN2 ,_, charged_VVD particles_NN2 move_VV0 under_II the_AT influence_NN1 of_IO the_AT Galactic_JJ Magnetic_JJ Field_NN1 ,_, diffusing_VVG and_CC losing_VVG energy_NN1 ,_, resulting_VVG in_II a_AT1 diffuse_JJ spectrum_NN1 at_II Earth_NN1 ._. 
By_II studying_VVG the_AT cosmic_JJ ray_NN1 antimatter_NN1 spectra_NN2 ,_, balloon_NN1 or_CC satellite-based_JJ experiments_NN2 hope_VV0 to_TO identify_VVI signatures_NN2 of_IO dark_JJ matter_NN1 ._. 
The_AT PAMELA_NN1 satellite_NN1 ,_, which_DDQ began_VVD its_APPGE three-year_JJ mission_NN1 in_II June_NPM1 of_IO 2006_MC ,_, is_VBZ designed_VVN to_II measure_NN1 the_AT spectra_NN2 of_IO cosmic_JJ ray_NN1 positrons_NN2 up_II21 to_II22 270GeV_FO and_CC electrons_NN2 up_II21 to_II22 2TeV_FO ,_, each_DD1 with_IW unprecedented_JJ precision_NN1 ._. 
Recent_JJ results_NN2 show_VV0 that_CST the_AT ratio_NN1 of_IO positrons_NN2 to_II electrons_NN2 plus_II positrons_NN2 (_( the_AT positron_NN1 fraction_NN1 )_) in_II the_AT cosmic_JJ ray_NN1 spectrum_NN1 appears_VVZ to_TO stop_VVI decreasing_JJ and_CC begins_VVZ to_TO climb_VVI quite_RG rapidly_RR between_II 10GeV_FO and_CC 100GeV_FO ._. 
A_AT1 similar_JJ trend_NN1 was_VBDZ in_II fact_NN1 also_RR indicated_VVN by_II earlier_JJR experiments_NN2 ,_, including_II HEAT_NN1 and_CC AMS-01_MC ,_, although_CS with_IW lesser_JJ statistical_JJ significance_NN1 ._. 
The_AT behavior_NN1 in_II the_AT positron_NN1 fraction_NN1 observed_VVN by_II PAMELA_NP1 is_VBZ very_RG different_JJ from_II that_DD1 predicted_VVD for_IF secondary_JJ positrons_NN2 produced_VVN in_II the_AT collisions_NN2 of_IO cosmic_JJ ray_NN1 nuclides_NN2 with_IW the_AT interstellar_JJ medium_NN1 ._. 
Barring_II systematics_NN2 (_( e.g._REX problems_NN2 in_II the_AT positron/proton_NN1 separation_NN1 at_II high_JJ rigidity_NN1 )_) ,_, the_AT data_NN appear_VV0 to_TO indicate_VVI the_AT existence_NN1 of_IO additional_JJ ,_, primary_JJ sources_NN2 of_IO high_JJ energy_NN1 positrons_NN2 ,_, such_II21 as_II22 dark_JJ matter_NN1 annihilations_NN2 taking_VVG place_NN1 in_II the_AT halo_NN1 of_IO the_AT Milky_JJ Way_NN1 ._. 
It_PPH1 should_VM be_VBI noted_VVN ,_, however_RR ,_, that_CST while_CS the_AT observed_JJ spectral_JJ shape_NN1 can_VM be_VBI easily_RR accommodated_VVN with_IW annihilating_VVG dark_JJ matter_NN1 ,_, the_AT normalization_NN1 of_IO this_DD1 contribution_NN1 to_II the_AT PAMELA_NN1 data_NN requires_VVZ a_AT1 somewhat_RR large_JJ annihilation_NN1 rate_NN1 ._. 
In_II either_DD1 case_NN1 ,_, such_DA scenarios_NN2 are_VBR somewhat_RR constrained_VVN by_II observations_NN2 of_IO gamma-rays_NN2 ,_, antiprotons_NN2 and_CC synchrotron_NN1 emission_NN1 ._. 
The_AT challenges_NN2 involved_JJ in_II explaining_VVG the_AT PAMELA_NN1 signal_NN1 with_IW annihilating_VVG dark_JJ matter_NN1 lead_VV0 us_PPIO2 to_TO consider_VVI a_AT1 less_RGR exotic_JJ and_CC purely_RR astrophysical_JJ explanation_NN1 for_IF the_AT observed_JJ positron_NN1 flux_NN1 ._. 
Energetic_JJ electron-positron_JJ pairs_NN2 can_VM be_VBI in_II fact_NN1 produced_VVN in_II astrophysical_JJ sources_NN2 ,_, the_AT leading_JJ candidate_NN1 sites_NN2 being_VBG pulsars_NN2 --_NN1 rapidly_RR spinning_VVG ,_, magnetized_VVD neutron_NN1 stars_NN2 ,_, which_DDQ emit_VV0 pulsed_JJ electromagnetic_JJ radiation_NN1 ,_, as_CSA observed_VVN from_II Earth_NN1 ._. 
In_II this_DD1 paper_NN1 ,_, we_PPIS2 explore_VV0 the_AT possibility_NN1 that_CST the_AT positron_NN1 fraction_NN1 reported_VVN by_II PAMELA_NP1 may_VM be_VBI generated_VVN by_II mature_JJ pulsars_NN2 ._. 
Gamma-ray_JJ pulsars_NN2 are_VBR predicted_VVN to_TO produce_VVI energetic_JJ electron-positron_JJ pairs_NN2 with_IW a_AT1 harder_JJR spectrum_NN1 than_CSN that_DD1 from_II secondary_JJ cosmic-ray_NN1 induced_VVD origin_NN1 ,_, leading_VVG to_II the_AT possibility_NN1 that_CST such_DA sources_NN2 may_VM dominate_VVI the_AT cosmic_JJ ray_NN1 positron_NN1 spectrum_NN1 at_II high_JJ energies_NN2 ._. 
We_PPIS2 calculate_VV0 the_AT spectrum_NN1 of_IO such_DA particles_NN2 from_II known_JJ local_JJ pulsars_NN2 (_( Geminga_NP1 and_CC B0656+14_FO )_) ,_, and_CC from_II the_AT sum_NN1 of_IO all_DB pulsars_NN2 distributed_VVN throughout_II the_AT Milky_JJ Way_NN1 ._. 
As_CSA found_VVN in_II earlier_JJR studies_NN2 ,_, we_PPIS2 find_VV0 that_CST both_DB2 local_JJ pulsars_NN2 and_CC the_AT sum_NN1 of_IO pulsars_NN2 distributed_VVN throughout_II the_AT Milky_JJ Way_NN1 can_VM contribute_VVI significantly_RR to_II the_AT observed_JJ spectrum_NN1 ._. 
At_II 10GeV_FO ,_, we_PPIS2 estimate_VV0 that_CST on_II average_NN1 only_RR 20%_NNU of_IO the_AT cosmic_JJ ray_NN1 positrons_NN2 originate_VV0 from_II pulsars_NN2 within_II 500_MC parsecs_NN2 from_II the_AT Solar_JJ System_NN1 ._. 
The_AT remainder_NN1 of_IO this_DD1 article_NN1 is_VBZ structured_VVN as_CSA follows_VVZ :_: In_II section_NN1 2_MC ,_, we_PPIS2 review_VV0 the_AT known_JJ properties_NN2 of_IO pulsars_NN2 and_CC consider_VV0 them_PPHO2 as_CSA sources_NN2 of_IO high_JJ energy_NN1 electron-positron_NN1 pairs_NN2 ._. 
In_II section_NN1 3_MC ,_, we_PPIS2 consider_VV0 the_AT nearby_JJ pulsars_NN2 Geminga_NP1 and_CC B0656+14_FO and_CC discuss_VV0 their_APPGE potential_JJ contributions_NN2 to_II the_AT cosmic_JJ ray_NN1 positron_NN1 spectrum_NN1 ._. 
In_II section_NN1 4_MC ,_, we_PPIS2 calculate_VV0 the_AT expected_JJ dipole_NN1 anisotropy_NN1 from_II nearby_JJ pulsars_NN2 and_CC compare_VV0 this_DD1 to_II the_AT sensitivity_NN1 of_IO the_AT Fermi_NP1 gamma-ray_JJ space_NN1 telescope_NN1 ._. 
We_PPIS2 summarize_VV0 and_CC draw_VV0 our_APPGE conclusions_NN2 in_II section_NN1 5_MC ._. 
In_II both_DB2 models_NN2 of_IO polar_JJ gap_NN1 and_CC outer_JJ gap_NN1 ,_, electrons_NN2 can_VM be_VBI accelerated_VVN in_II different_JJ regions_NN2 of_IO the_AT pulsar_NN1 magnetosphere_NN1 and_CC induce_VV0 an_AT1 electromagnetic_JJ cascade_NN1 through_II the_AT emission_NN1 of_IO curvature_NN1 radiation_NN1 ,_, which_DDQ in_II turn_NN1 results_NN2 in_II production_NN1 of_IO photons_NN2 which_DDQ are_VBR above_JJ threshold_NN1 for_IF pair_NN production_NN1 in_II the_AT strong_JJ pulsar_NN1 magnetic_JJ field_NN1 ._. 
This_DD1 process_NN1 results_NN2 in_II lower_JJR energy_NN1 electrons_NN2 and_CC positrons_NN2 that_CST can_VM escape_VVI the_AT magnetosphere_NN1 either_RR through_II the_AT open_JJ field_NN1 lines_NN2 or_CC after_II joining_VVG the_AT pulsar_NN1 wind_NN1 ._. 
In_II this_DD1 second_NNT1 case_NN1 ,_, the_AT electrons_NN2 and_CC positrons_NN2 lose_VV0 part_NN1 of_IO their_APPGE energy_NN1 adiabatically_RR because_II21 of_II22 the_AT expansion_NN1 of_IO the_AT wind_NN1 ._. 
The_AT energy_NN1 spectrum_NN1 injected_VVN by_II a_AT1 single_JJ pulsar_NN1 depends_VVZ on_II the_AT environmental_JJ parameters_NN2 of_IO the_AT pulsar_NN1 ,_, but_CCB some_DD attempts_NN2 to_TO calculate_VVI the_AT average_JJ spectrum_NN1 injected_VVN by_II a_AT1 population_NN1 of_IO mature_JJ pulsars_NN2 suggest_VV0 that_CST the_AT spectrum_NN1 may_VM be_VBI relatively_RR hard_JJ ,_, having_VHG a_AT1 slope_NN1 of_IO This_DD1 spectrum_NN1 ,_, however_RR ,_, results_NN2 from_II a_AT1 complex_JJ interplay_NN1 of_IO individual_JJ pulsar_NN1 spectra_NN2 ,_, of_IO the_AT spatial_JJ and_CC age_NN1 distributions_NN2 of_IO pulsars_NN2 in_II the_AT Galaxy_NN1 ,_, and_CC on_II the_AT assumption_NN1 that_CST the_AT chief_JJ channel_NN1 for_IF pulsar_NN1 spin_VV0 down_RP is_VBZ magnetic_JJ dipole_NN1 radiation_NN1 ._. 
Due_II21 to_II22 the_AT related_JJ uncertainties_NN2 ,_, variations_NN2 from_II this_DD1 injection_NN1 spectra_NN2 can_VM not_XX be_VBI ruled_VVN out_RP ._. 
Typically_RR ,_, one_PN1 concentrates_VVZ the_AT attention_NN1 on_II pulsars_NN2 of_IO 105_MC years_NNT2 because_CS younger_JJR pulsars_NN2 are_VBR likely_JJ to_TO still_RR be_VBI surrounded_VVN by_II their_APPGE nebulae_NN2 ,_, which_DDQ confine_VV0 electrons_NN2 and_CC positrons_NN2 and_CC thus_RR prevent_VV0 them_PPHO2 from_II being_VBG liberated_VVN into_II the_AT interstellar_JJ medium_NN1 until_CS later_JJR times_NNT2 ._. 
Still_RR ,_, some_DD energetics_NN1 considerations_NN2 can_VM be_VBI done_VDN with_IW simple_JJ analytical_JJ models_NN2 ;_; this_DD1 will_VM also_RR help_VVI the_AT understanding_NN1 of_IO arguments_NN2 developed_VVN in_II the_AT next_MD section_NN1 ._. 
The_AT rate_NN1 of_IO energy_NN1 injection_NN1 from_II a_AT1 single_JJ pulsar_NN1 in_II the_AT form_NN1 of_IO pairs_NN2 is_VBZ limited_VVN by_II its_APPGE spin-down_JJ power_NN1 (_( the_AT rate_NN1 of_IO energy_NN1 loss_NN1 corresponding_VVG to_II the_AT slowing_JJ rate_NN1 of_IO rotation_NN1 )_) ._. 
To_TO proceed_VVI in_II a_AT1 more_RGR quantitative_JJ way_NN1 towards_II the_AT calculation_NN1 of_IO the_AT overall_JJ spectrum_NN1 from_II Galactic_JJ pulsars_NN2 ,_, one_PN1 needs_VVZ to_TO adopt_VVI a_AT1 model_NN1 for_IF the_AT e+_FO ?_? e_ZZ1 ?_? acceleration_NN1 and_CC escape_VV0 probability_NN1 from_II a_AT1 single_JJ pulsar_NN1 with_IW a_AT1 given_JJ magnetic_JJ field_NN1 ,_, period_NN1 ,_, etc._RA and_CC then_RT integrate_VV0 over_RP a_AT1 Monte_NP1 Carlo_NP1 distribution_NN1 of_IO these_DD2 typical_JJ parameters_NN2 in_II a_AT1 Galactic_JJ Pulsar_NN1 population_NN1 ._. 
In_II figure_NN1 1_MC1 ,_, we_PPIS2 show_VV0 the_AT spectrum_NN1 of_IO positrons_NN2 and_CC the_AT positron_NN1 fraction_NN1 resulting_VVG from_II the_AT sum_NN1 of_IO all_DB pulsars_NN2 throughout_II the_AT Milky_JJ Way_NN1 ._. 
In_II the_AT upper_JJ panels_NN2 ,_, we_PPIS2 show_VV0 results_NN2 for_IF different_JJ rates_NN2 of_IO pulsar_NN1 birth_NN1 (_( one_MC1 per_II 10_MC ,_, 25_MC ,_, or_CC 100_MC years_NNT2 )_) ._. 
The_AT dashed_JJ line_NN1 represents_VVZ the_AT baseline_NN1 result_NN1 neglecting_VVG the_AT contribution_NN1 from_II pulsars_NN2 ,_, including_VVG only_RR the_AT positrons_NN2 produced_VVN as_CSA secondaries_NN2 in_II the_AT hadronic_JJ interaction_NN1 of_IO cosmic_JJ rays_NN2 ._. 
In_II the_AT right_JJ frames_NN2 ,_, the_AT positron_NN1 ratio_NN1 is_VBZ obtained_VVN considering_CS ,_, besides_RR secondary_JJ leptons_NN2 ,_, also_RR the_AT primary_JJ electrons_NN2 accounted_VVN as_CSA in_II ,_, to_TO ease_VVI the_AT comparison_NN1 with_IW previous_JJ literature_NN1 ._. 
In_II the_AT right_JJ frames_NN2 ,_, the_AT measurements_NN2 of_IO HEAT_NN1 (_( light_JJ green_NN1 and_CC magenta_NN1 )_) and_CC the_AT measurements_NN2 of_IO PAMELA_NP1 (_( dark_JJ red_NN1 )_) are_VBR also_RR shown_VVN ._. 
The_AT cutoff_NN1 in_II the_AT positron_NN1 spectrum_NN1 derived_VVN in_II our_APPGE calculations_NN2 is_VBZ solely_RR the_AT result_NN1 of_IO the_AT corresponding_JJ cutoff_NN1 in_II the_AT injection_NN1 spectrum_NN1 shown_VVN in_II eq_NN1 ._. 
(_( 2.7_MC )_) ._. 
This_DD1 cutoff_NN1 is_VBZ determined_VVN by_II the_AT details_NN2 of_IO the_AT development_NN1 of_IO the_AT electromagnetic_JJ cascade_NN1 in_II the_AT pulsar_NN1 magnetosphere_NN1 and_CC ,_, even_RR more_RGR importantly_RR ,_, by_II the_AT distribution_NN1 of_IO periods_NN2 ,_, magnetic_JJ fields_NN2 ,_, and_CC radii_NN2 of_IO mature_JJ pulsars_NN2 ._. 
The_AT exact_JJ value_NN1 of_IO the_AT cutoff_NN1 energy_NN1 should_VM ,_, therefore_RR ,_, not_XX be_VBI considered_VVN to_TO be_VBI a_AT1 robust_JJ prediction_NN1 of_IO the_AT theory_NN1 ,_, although_CS it_PPH1 represents_VVZ a_AT1 good_JJ estimate_NN1 of_IO the_AT order_NN1 of_IO magnitude_NN1 of_IO the_AT cutoff_NN1 energy_NN1 ._. 
For_REX21 instance_REX22 ,_, in_II ref._NN1 it_PPH1 is_VBZ argued_VVN that_CST the_AT typical_JJ energy_NN1 of_IO electrons_NN2 and_CC positrons_NN2 in_II the_AT cascade_NN1 associated_VVN with_IW the_AT polar_JJ gap_NN1 is_VBZ at_II energies_NN2 lower_JJR than_CSN 10GeV_FO ,_, pulsars_NN2 are_VBR not_XX expected_VVN to_TO contribute_VVI any_DD appreciable_JJ flux_NN1 because_II21 of_II22 the_AT very_RG hard_JJ spectrum_NN1 ,_, compared_VVN to_II the_AT spectrum_NN1 of_IO secondary_JJ positrons_NN2 produced_VVN in_II hadronic_JJ interactions_NN2 of_IO cosmic_JJ rays_NN2 diffusing_VVG throughout_II the_AT Galaxy_NN1 ._. 
These_DD2 secondary_JJ electrons_NN2 approximately_RR reproduce_VV0 the_AT steep_JJ spectrum_NN1 of_IO the_AT parent_NN1 nuclei_NN2 and_CC at_II low_JJ energies_NN2 dominate_VV0 the_AT observed_JJ positron_NN1 fraction_NN1 ._. 
Since_CS the_AT spectrum_NN1 of_IO positrons_NN2 from_II pulsars_NN2 is_VBZ important_JJ only_RR at_II relatively_RR high_JJ energies_NN2 ,_, we_PPIS2 have_VH0 neglected_VVN here_RL the_AT role_NN1 of_IO solar_JJ modulation_NN1 ._. 
Nearby_JJ pulsars_NN2 as_II a_AT1 source_NN1 of_IO high_JJ energy_NN1 cosmic_JJ ray_NN1 electrons_NN2 and_CC positrons_NN2 In_II this_DD1 section_NN1 ,_, following_VVG earlier_JJR studies_NN2 ,_, we_PPIS2 re-explore_VV0 the_AT possibility_NN1 that_CST an_AT1 individual_JJ or_CC small_JJ number_NN1 of_IO nearby_JJ pulsars_NN2 dominate_VV0 the_AT cosmic_JJ ray_NN1 positron_NN1 spectrum_NN1 within_II the_AT energy_NN1 range_NN1 studied_VVN by_II PAMELA_NP1 ._. 
As_CSA argued_VVN in_II the_AT previous_JJ section_NN1 ,_, in_BCL21 order_BCL22 to_TO contribute_VVI significantly_RR such_DA a_AT1 pulsar_NN1 can_VM be_VBI neither_RR too_RG young_JJ nor_CC too_RG old_JJ ._. 
The_AT spectrum_NN1 of_IO electron_NN1 positron_NN1 pairs_NN2 at_II Earth_NN1 is_VBZ again_RT calculated_VVN by_II solving_VVG the_AT transport_NN1 equation_NN1 ,_, but_CCB this_DD1 time_NNT1 for_IF a_AT1 single_JJ source_NN1 ._. 
Moreover_RR we_PPIS2 consider_VV0 the_AT case_NN1 of_IO a_AT1 bursting_JJ source_NN1 ,_, namely_REX one_PN1 in_II which_DDQ the_AT duration_NN1 of_IO the_AT emission_NN1 is_VBZ much_RR shorter_JJR than_CSN the_AT travel_NN1 time_NNT1 from_II the_AT source_NN1 ._. 
For_IF the_AT pulsars_NN2 discussed_VVN above_RL this_DD1 seems_VVZ indeed_RR to_TO be_VBI appropriate_JJ ._. 
For_IF the_AT simple_JJ case_NN1 of_IO a_AT1 power-law_NN1 spectrum_NN1 of_IO electrons_NN2 and_CC positrons_NN2 ._. 
The_AT Fermi_NP1 sensitivity_NN1 shown_VVN is_VBZ for_IF the_AT spectrum_NN1 integrated_VVN above_II a_AT1 given_JJ energy_NN1 ._. 
In_II figure_NN1 5_MC we_PPIS2 plot_VV0 the_AT level_NN1 of_IO anisotropy_NN1 expected_VVN for_IF a_AT1 Geminga-like_JJ and_CC a_AT1 B0656+14-like_FO pulsar_VV0 if_CSW they_PPHS2 are_VBR responsible_JJ for_IF the_AT majority_NN1 of_IO the_AT observed_JJ positron_NN1 excess_NN1 ._. 
The_AT two_MC dashed_JJ lines_NN2 show_VV0 the_AT sensitivities_NN2 of_IO Fermi_NP1 to_II anisotropy_NN1 at_II 95_MC confidence_NN1 level_NN1 and_CC at_II 5_MC &sigma;_NULL confidence_NN1 level_NN1 ,_, after_II five_MC years_NNT2 of_IO observation_NN1 (_( integrated_VVN above_II a_AT1 given_JJ energy_NN1 )_) ._. 
We_PPIS2 find_VV0 that_CST Fermi_NP1 should_VM be_VBI capable_JJ of_IO identifying_VVG a_AT1 single_JJ local_JJ source_NN1 (_( or_CC multiple_JJ sources_NN2 in_II the_AT same_DA direction_NN1 of_IO the_AT sky_NN1 )_) if_CS that_DD1 source_NN1 injected_VVD the_AT bulk_NN1 of_IO its_APPGE electrons/positrons_NN2 within_II the_AT last_MD few_DA2 hundred_NNO thousand_NNO years_NNT2 (_( the_AT B0656+14-like_FO and_CC Geminga-like_JJ cases_NN2 correspond_VV0 to_II injection_NN1 110,000_MC and_CC 370,000_MC years_NNT2 ago_RA ,_, respectively_RR )_) ._. 
If_CS only_RR a_AT1 fraction_NN1 of_IO the_AT high_JJ energy_NN1 positrons_NN2 observed_VVN by_II PAMELA_NP1 originate_VV0 from_II a_AT1 given_JJ nearby_JJ pulsar_NN1 ,_, the_AT corresponding_JJ solid_JJ lines_NN2 shown_VVN in_II figure_NN1 5_MC should_VM be_VBI multiplied_VVN (_( reduced_VVN )_) by_II this_DD1 factor_NN1 ._. 
Alternatively_RR ,_, if_CS dark_JJ matter_NN1 annihilations_NN2 throughout_II the_AT Milky_JJ Way_NN1 's_GE halo_NN1 are_VBR primarily_RR responsible_JJ for_IF the_AT excess_NN1 in_II the_AT high_JJ energy_NN1 cosmic_JJ ray_NN1 positron_NN1 spectrum_NN1 ,_, a_AT1 small_JJ dipole_NN1 anisotropy_NN1 in_II the_AT direction_NN1 of_IO the_AT Galactic_JJ Center_NN1 could_VM also_RR be_VBI generated_VVN ._. 
Fortunately_RR ,_, both_DB2 B0656+14_FO and_CC Geminga_NP1 are_VBR in_II approximately_RR the_AT opposite_JJ direction_NN1 ,_, allowing_VVG for_IF a_AT1 potentially_RR unambiguous_JJ discrimination_NN1 between_II these_DD2 possibilities_NN2 ._. 
In_II the_AT special_JJ and_CC relatively_RR unlikely_JJ case_NN1 that_CST a_AT1 nearby_JJ dark_JJ matter_NN1 subhalo_NN1 in_II the_AT direction_NN1 of_IO B0656+14/Geminga_NN1 is_VBZ responsible_JJ for_IF the_AT observed_JJ flux_NN1 ,_, it_PPH1 would_VM be_VBI difficult_JJ to_TO distinguish_VVI between_II pulsar_NN1 and_CC dark_JJ matter_NN1 origins_NN2 using_VVG this_DD1 technique_NN1 ._. 
If_CS anisotropy_NN1 studies_NN2 should_VM prove_VVI inconclusive_JJ in_II resolving_VVG this_DD1 issue_NN1 ,_, other_JJ information_NN1 could_VM be_VBI inferred_VVN from_II the_AT shape_NN1 of_IO the_AT positron_NN1 fraction_NN1 and_CC of_IO the_AT overall_JJ electron/positron_NN1 spectrum_NN1 ._. 
Peculiar_JJ shapes_NN2 can_VM result_VVI from_II the_AT superposition_NN1 of_IO the_AT overall_JJ pulsar_NN1 spectrum_NN1 plus_II local_JJ contributions_NN2 (_( see_VV0 ,_, for_REX21 example_REX22 ,_, figure_NN1 4_MC or_CC ref_NN1 )_) ._. 
Future_JJ studies_NN2 of_IO the_AT electron_NN1 and_CC positron_NN1 spectra_NN2 at_II higher_JJR energies_NN2 will_VM be_VBI especially_RR important_JJ ,_, as_CSA the_AT spectral_JJ cutoff_NN1 in_II the_AT pulsar_NN1 case_NN1 is_VBZ typically_RR expected_VVN to_TO be_VBI smoother_JJR and_CC less_RGR sudden_JJ than_CSN that_DD1 predicted_VVD from_II annihilating_VVG dark_JJ matter_NN1 ._. 
Furthermore_RR ,_, combining_VVG electron/positron_NN1 measurements_NN2 with_IW those_DD2 of_IO antiprotons_NN2 ,_, antideuterons_NN2 and_CC diffuse_JJ gamma-rays_NN2 may_VM prove_VVI useful_JJ in_II distinguishing_VVG between_II these_DD2 possibilities_NN2 ._. 
Population_NN1 studies_NN2 of_IO pulsars_NN2 in_II the_AT gamma-ray_JJ band_NN1 by_II Fermi_NP1 are_VBR also_RR expected_VVN to_TO refine_VVI theoretical_JJ predictions_NN2 and_CC shed_VVI light_NN1 on_II this_DD1 issue._NNU 5_MC Conclusions_NN2 The_AT results_NN2 recently_RR reported_VVN by_II PAMELA_NP1 strongly_RR indicate_VV0 the_AT existence_NN1 of_IO a_AT1 primary_JJ source_NN1 or_CC sources_NN2 of_IO high_JJ energy_NN1 cosmic_JJ ray_NN1 positrons_NN2 ._. 
This_DD1 result_NN1 is_VBZ very_RG interesting_JJ ,_, even_CS21 if_CS22 of_IO purely_RR astrophysical_JJ origin_NN1 ._. 
Several_DA2 papers_NN2 have_VH0 appeared_VVN recently_RR which_DDQ discuss_VV0 this_DD1 signal_NN1 within_II the_AT context_NN1 of_IO dark_JJ matter_NN1 annihilations_NN2 ._. 
In_II this_DD1 article_NN1 ,_, we_PPIS2 have_VH0 instead_RR explored_VVN the_AT possibility_NN1 that_CST the_AT observed_JJ flux_NN1 of_IO high_JJ energy_NN1 positrons_NN2 is_VBZ the_AT result_NN1 of_IO electron-positron_JJ pairs_NN2 being_VBG produced_VVN in_II nearby_RL and_CC galactic_JJ pulsars_NN2 ._. 
We_PPIS2 find_VV0 that_CST pulsars_VVZ throughout_II the_AT Milky_JJ Way_NN1 ,_, and_CC a_AT1 small_JJ number_NN1 of_IO nearby_JJ mature_JJ pulsars_NN2 ,_, such_II21 as_II22 B0656+14_FO and_CC Geminga_NP1 ,_, could_VM each_DD1 plausibly_RR generate_VVI the_AT observed_JJ flux_NN1 of_IO positrons_NN2 ._. 
To_TO normalize_VVI the_AT overall_JJ flux_NN1 ,_, on_II the_AT order_NN1 of_IO a_AT1 few_DA2 percent_NNU of_IO the_AT pulsars_NN2 '_GE spin_NN1 down_II power_NN1 is_VBZ required_VVN to_TO be_VBI transferred_VVN into_II the_AT production_NN1 of_IO electron-positron_JJ pairs_NN2 ._. 
The_AT prediction_NN1 in_II the_AT case_NN1 of_IO the_AT sum_NN1 of_IO all_DB pulsars_NN2 in_II the_AT Galaxy_NN1 appears_VVZ somewhat_RR more_RGR robust_JJ in_CS21 that_CS22 it_PPH1 relies_VVZ on_II the_AT average_JJ statistical_JJ properties_NN2 of_IO these_DD2 astrophysical_JJ objects_NN2 rather_II21 than_II22 on_II the_AT specific_JJ characteristics_NN2 of_IO nearby_JJ pulsars_NN2 ._. 
It_PPH1 is_VBZ remarkable_JJ that_CST in_II this_DD1 case_NN1 ,_, reasonable_JJ values_NN2 for_IF the_AT parameters_NN2 can_VM lead_VVI to_II a_AT1 positron_NN1 spectrum_NN1 consistent_JJ with_IW the_AT observations_NN2 ._. 
Also_RR ,_, a_AT1 pulsar_NN1 origin_NN1 would_VM naturally_RR fit_VVI the_AT absence_NN1 of_IO an_AT1 excess_NN1 in_II the_AT anti-proton_JJ data_NN ,_, since_CS differently_RR from_II dark_JJ matter_NN1 scenarios_NN2 no_AT hadronic_JJ cascades_NN2 are_VBR associated_VVN with_IW the_AT production_NN1 of_IO pairs_NN2 in_II the_AT magnetospheres_NN2 ._. 
