Z. Balog - Academia.edu (original) (raw)

Papers by Z. Balog

We present results of an infrared study of the molecular cloud Lynds 1340, forming three groups o... more We present results of an infrared study of the molecular cloud Lynds 1340, forming three groups of low and intermediate-mass stars. Our goals are to identify and characterise the young stellar population of the cloud, study the relationships between the properties of the cloud and the emergent stellar groups, and integrate L1340 into the picture of the star-forming activity of our Galactic environment. We selected candidate young stellar objects from the Spitzer and WISE data bases using various published color criteria, and classified them based on the slope of the spectral energy distribution. We identified 170 Class II, 27 Flat SED, and 45 Class 0/I sources. High angular resolution near-infrared observations of the RNO 7 cluster, embedded in L1340, revealed eight new young stars of near-infrared excess. The surface density distribution of young stellar objects shows three groups, associated with the three major molecular clumps of L1340, each consisting of 100 members, including both pre-main sequence stars and embedded protostars. New Herbig–Haro objects were identified in the Spitzer images. Our results demonstrate that L1340 is a prolific star-forming region of our Galactic environment in which several specific properties of the intermediate-mass mode of star formation can be studied in detail.

Astrophysics and Space Science Library, 2005

Page 1. PRELIMINARY RESULTS ON NEWLY DISCOVERED EMBEDDED CLUSTERS András Gáspár,1 Zoltán Balog,1 ... more Page 1. PRELIMINARY RESULTS ON NEWLY DISCOVERED EMBEDDED CLUSTERS András Gáspár,1 Zoltán Balog,1 Zoltán Makai,2 József Vinkó,1 and Scott J. Kenyon3 1 Dept. of Optics and Quantum Electronics, University of Szeged, Szeged, Hungary 2 Dept. ...

The Astronomical Journal, 2006

We present UBVRI photometry of 44 Type Ia supernovae (SNe Ia) observed from 1997 to 2001 as part ... more We present UBVRI photometry of 44 Type Ia supernovae (SNe Ia) observed from 1997 to 2001 as part of a continuing monitoring campaign at the Fred Lawrence Whipple Observatory of the Harvard-Smithsonian Center for Astrophysics. The data set comprises 2190 observations and is the largest homogeneously observed and reduced sample of SNe Ia to date, nearly doubling the number of well-observed, nearby SNe Ia with published multicolor CCD light curves. The large sample of U-band photometry is a unique addition, with important connections to SNe Ia observed at high redshift. The decline rate of SN Ia U-band light curves correlates well with the decline rate in other bands, as does the U À B color at maximum light. However, the U-band peak magnitudes show an increased dispersion relative to other bands even after accounting for extinction and decline rate, amounting to an additional $40% intrinsic scatter compared to the B band.

The Astronomical Journal, 2004

We describe the results of two near infrared (K-band) imaging surveys and a three color (JHK) sur... more We describe the results of two near infrared (K-band) imaging surveys and a three color (JHK) survey of the vicinity of NGC 7538. The limiting magnitudes are K ≃ 16.5 and K ≃ 17.5 mag for the K-band surveys and K ≃ 15 mag for the JHK survey. We identify more than 2000 and 9000 near-infrared (NIR) sources on the images of the two 1 Observations reported here were obtained at the MMT Observatory, a joint facility of the Smithsonian Institution and the University of Arizona.

Astronomy and Astrophysics, 2009

Aims. We report the outcome of a deep multiwavelength study of the IC 2391 young open cluster. We... more Aims. We report the outcome of a deep multiwavelength study of the IC 2391 young open cluster. We attempt to uncover new lowmass and sub-stellar members of the cluster and identify new debris disk objects. Methods. We observed a 30 × 30 square arcmin area in IC 2391 using the wide-field imager at the ESO 2.2 m telescope. The completeness limits of the photometry at the 3σ level are V = 24.7, R C = 23.7, and I C = 23.0, faint enough to reveal sub-stellar members down to ∼0.03 M . Our membership criteria are based on use of our optical data in combination with JHK S magnitudes from the 2MASS catalog. We also estimate the physical parameters of the selected candidates. Debris disk candidates are identified on the basis of their infrared excess emission using near-and mid-infrared photometry from the Spitzer Space Telescope. Results. Our optical survey, which has a limiting magnitude at the 3σ level 1-2 mag fainter than previous optical surveys conducted in IC 2391, revealed 29 new low-mass member candidates of the cluster. We estimate the contamination to be at least ∼50%. We constrain the fraction of sub-stellar objects in the range 8-15% and discuss possible explanations of the deficit of brown dwarfs in this cluster. We also identify 10 candidates in the cluster showing IR excess emission consistent with the presence of debris disks.

We present results of an infrared study of the molecular cloud Lynds 1340, forming three groups o... more We present results of an infrared study of the molecular cloud Lynds 1340, forming three groups of low and intermediate-mass stars. Our goals are to identify and characterise the young stellar population of the cloud, study the relationships between the properties of the cloud and the emergent stellar groups, and integrate L1340 into the picture of the star-forming activity of our Galactic environment. We selected candidate young stellar objects from the Spitzer and WISE data bases using various published color criteria, and classified them based on the slope of the spectral energy distribution. We identified 170 Class II, 27 Flat SED, and 45 Class 0/I sources. High angular resolution near-infrared observations of the RNO 7 cluster, embedded in L1340, revealed eight new young stars of near-infrared excess. The surface density distribution of young stellar objects shows three groups, associated with the three major molecular clumps of L1340, each consisting of 100 members, including both pre-main sequence stars and embedded protostars. New Herbig–Haro objects were identified in the Spitzer images. Our results demonstrate that L1340 is a prolific star-forming region of our Galactic environment in which several specific properties of the intermediate-mass mode of star formation can be studied in detail.

Astrophysics and Space Science Library, 2005

Page 1. PRELIMINARY RESULTS ON NEWLY DISCOVERED EMBEDDED CLUSTERS András Gáspár,1 Zoltán Balog,1 ... more Page 1. PRELIMINARY RESULTS ON NEWLY DISCOVERED EMBEDDED CLUSTERS András Gáspár,1 Zoltán Balog,1 Zoltán Makai,2 József Vinkó,1 and Scott J. Kenyon3 1 Dept. of Optics and Quantum Electronics, University of Szeged, Szeged, Hungary 2 Dept. ...

The Astronomical Journal, 2006

We present UBVRI photometry of 44 Type Ia supernovae (SNe Ia) observed from 1997 to 2001 as part ... more We present UBVRI photometry of 44 Type Ia supernovae (SNe Ia) observed from 1997 to 2001 as part of a continuing monitoring campaign at the Fred Lawrence Whipple Observatory of the Harvard-Smithsonian Center for Astrophysics. The data set comprises 2190 observations and is the largest homogeneously observed and reduced sample of SNe Ia to date, nearly doubling the number of well-observed, nearby SNe Ia with published multicolor CCD light curves. The large sample of U-band photometry is a unique addition, with important connections to SNe Ia observed at high redshift. The decline rate of SN Ia U-band light curves correlates well with the decline rate in other bands, as does the U À B color at maximum light. However, the U-band peak magnitudes show an increased dispersion relative to other bands even after accounting for extinction and decline rate, amounting to an additional $40% intrinsic scatter compared to the B band.

The Astronomical Journal, 2004

We describe the results of two near infrared (K-band) imaging surveys and a three color (JHK) sur... more We describe the results of two near infrared (K-band) imaging surveys and a three color (JHK) survey of the vicinity of NGC 7538. The limiting magnitudes are K ≃ 16.5 and K ≃ 17.5 mag for the K-band surveys and K ≃ 15 mag for the JHK survey. We identify more than 2000 and 9000 near-infrared (NIR) sources on the images of the two 1 Observations reported here were obtained at the MMT Observatory, a joint facility of the Smithsonian Institution and the University of Arizona.

Astronomy and Astrophysics, 2009

Aims. We report the outcome of a deep multiwavelength study of the IC 2391 young open cluster. We... more Aims. We report the outcome of a deep multiwavelength study of the IC 2391 young open cluster. We attempt to uncover new lowmass and sub-stellar members of the cluster and identify new debris disk objects. Methods. We observed a 30 × 30 square arcmin area in IC 2391 using the wide-field imager at the ESO 2.2 m telescope. The completeness limits of the photometry at the 3σ level are V = 24.7, R C = 23.7, and I C = 23.0, faint enough to reveal sub-stellar members down to ∼0.03 M . Our membership criteria are based on use of our optical data in combination with JHK S magnitudes from the 2MASS catalog. We also estimate the physical parameters of the selected candidates. Debris disk candidates are identified on the basis of their infrared excess emission using near-and mid-infrared photometry from the Spitzer Space Telescope. Results. Our optical survey, which has a limiting magnitude at the 3σ level 1-2 mag fainter than previous optical surveys conducted in IC 2391, revealed 29 new low-mass member candidates of the cluster. We estimate the contamination to be at least ∼50%. We constrain the fraction of sub-stellar objects in the range 8-15% and discuss possible explanations of the deficit of brown dwarfs in this cluster. We also identify 10 candidates in the cluster showing IR excess emission consistent with the presence of debris disks.